The claim

Railway Alignment Designer lays out a railway in plan and profile, works the cant and transition lengths out from the design speed, checks the result against the governing standard, and produces setting-out tables, drawings and schedules. Given two points on a map it will fetch the terrain, search a corridor, fit geometry to it, fit a grade line to the ground, propose the structures the profile implies, price the lot on the Indian Railways plan heads, and tell you every place the design departs from the standard and what to do about each one.

On a 50 km corridor that whole pass takes about ten seconds in the browser. The worked example this manual is illustrated from — 58 km across the Maharashtra plateau — designs, repairs and checks itself in under a minute on an ordinary laptop.

The five things it does that a drafting package does not

1. It routes. A* over an elevation grid, one search per leg between the points you have pinned, with the cost blending length, cross slope, height gained beyond what the ruling gradient can absorb, and heading change.
2. It checks itself against a standard, continuously, and every finding carries the measurement, the limit, the clause, the reason the limit exists and the ways out.
3. It repairs. Most failures have a Fix; the ones that would need the route or the design speed changed decline and state the trade-off instead of guessing.
4. It knows what it does not know. A total is withheld rather than shown without its bridges; an empty map answer that no second source confirmed is reported as did not load rather than as a plausible zero; ground that nobody surveyed is hatched rather than painted.
5. It prices the design and keeps an editable bill. The generated estimate follows earthwork, crossings and stations. The detailed estimate stores the engineer's component quantities, measurements and adopted rates. An imported design bill is a fixed snapshot; review it when the alignment changes (Chapter 13).

The principles behind the code

What is in the box

Who decides what

The dividing line runs through the whole application and it is worth stating once. The tool decides arithmetic: what the cant should be for that radius and speed, whether 6.25 m of clearance exists, how much earth is in that cutting, what a 1 in 8.5 turnout does to the fouling mark. The engineer decides engineering: where the line should go, what speed the line is for, which side of the existing formation to build on, whether a warning is acceptable on this project, and whether any of it is true on the ground.

A program that quietly coarsened a setting on the engineer's behalf would be lying about what it had designed.

Start in the browser

The workspace is a web application. Open www.radrailway.com in a browser and it is running: no download, no installer, no licence file, no plug-in, and nothing to keep updated — new releases are delivered by the site. Close older application tabs to let a waiting update activate.

The desktop edition

Open the website's Free & Pro section and sign in with an active Pro account to request a Windows or macOS installer. Installer delivery checks the account's Pro entitlement; a visible download button by itself does not grant access. Choose the Mac build matching your processor when architecture choices are offered.

Install and open RAD, then use Open and Save for native .rads projects. The Windows installer and Mac application associate the project extension with the RAD logo; the portable Windows package does not install file associations. File icons are an operating-system association: a copied project cannot force its icon on a computer without RAD installed, and another application selected as the default can override that association.

Use Ctrl on Windows and ⌘ on macOS for the native file shortcuts. Internet services such as account verification, maps and live terrain still require connectivity. The desktop window does not turn absent online survey data into an offline dataset.

What it needs

A browser

Any current Chromium, Edge, Firefox or Safari. Saving straight back to a file on your own disk needs the File System Access API, which Chromium-based browsers have; elsewhere saving degrades to a download and says so rather than pretending the file is being kept current.

An account

Free to create, and it buys the project hub — your projects kept across machines with revision history. Sharing with a colleague, creating review links and team editing require Pro; read-only recipients can view for free. Sign-in is required on the configured website; deliverable downloads can also require Pro access. Work can also be kept purely as files on your own computer.

A network

For terrain, basemaps, corridor features, place search and the project hub. Each of those degrades on its own without taking the rest with it, and a corridor whose terrain has already been fetched will design again with no signal at all.

A screen

Designed for a laptop display and above. The plan takes the whole window with Shift+F, and the side panel folds to its icons with [.

Offline, and as an installed application

The application keeps a complete version of its interface for offline use; a new version waits for the previous version's tabs to close before taking over. Terrain tiles are cached separately in the browser. A web app manifest is included, so the workspace can be installed to a desktop or a phone home screen and opened without browser furniture.

Where the documentation lives

The first launch

The workspace opens empty — a single straight kilometre, because the geometry solver needs two points to have a line at all. Then two gates, in order.

1. Sign in. The workspace sits behind an account, because that is what projects are saved against, what lets them follow you between machines, and who a shared project is shared with. The panel has no close button, no Esc, no click-away and no way past — a gate with a dismiss control is not a gate. The same gate stands in front of the reference page, your profile and this manual; only the front page is open. If the account host cannot be reached the gate says so and offers to try again, rather than letting you in: it used to let you in, which also meant anyone able to stop one request could open it. It lifts entirely only for a build with no cloud project configured, where there are no accounts to check against.
2. What to do. The question in Figure 2.2.

Opening and saving

A project lives in one of two places — a file on this computer, or the project hub behind the sign-in — and which one is asked once, the first time it is saved. After that Save puts it back where it came from.

1. Use File › Open for an existing project, or Save as to choose a new destination. A project opened from the hub normally saves back to that cloud project.
2. Wait for any missing data you want to retain locally to finish restoring, then press Save. A file can only include terrain and map data that are available at that moment.
3. Check the shared save/status button: Save means there are unsaved changes, Saving… means the write is in progress, and Saved confirms completion. Its tooltip identifies the destination and time.

Autosave protects every committed edit in separate browser recovery storage and never changes the original file or cloud project. Normal refresh restores that working copy, still marked unsaved until you explicitly save. In Chrome, hard refresh opens an empty workspace; Recover unsaved draft restores the separate checkpoint if wanted. Refresh does not recalculate original ground. IP geometry edits update only the affected sections and retain unchanged ground at its adjusted chainages. Ctrl+S saves, Ctrl+O opens. Recovery protects the working copy; it does not replace an explicit file or cloud save. Unapplied bridge or estimate drafts must first be applied to join that project recovery copy.

A project by link

Cloud projects have addresses: app.html?project=<id>. A link is an explicit request for a particular project and beats both the recovered draft and the opening question — but never the sign-in gate, because the link says what to open, not who is allowed to open it. A project shared with you rather than owned by you opens read-only, and saving makes a project of your own.

Follow work in progress

The small activity strip at the bottom left reports the operation currently in progress. A percentage is shown when the operation reports measurable progress; an animated bar means work is continuing without a known total. Figure 16.2 shows the strip during a project export. When more than one operation is active, the indicator keeps the running work visible. Read the named task before repeating a long-running command.

Completion or an error updates the activity state. If the task reports a service failure, follow the displayed recovery action and retain the saved project. A progress indication is not proof that remote map or terrain data has already arrived.

Find commands by task

The header separates task groups from the four engineering stages. Select Data, Alignment, Structures, Stations, Review or Output to reveal that group's commands. Selecting a group changes the toolbar only; it does not alter the design or pass a stage gate. A command that needs a later stage opens its prerequisite checklist before proceeding.

The arrow beside the groups folds the command row; selecting a group opens it again. On compact screens the tabs can show icons: hover or focus them for their names. Arrow keys, Home and End move between the group tabs. File, undo/redo, Find a command, Display, Help, the save/status button and account remain in the header. Use Display for theme and the second-screen profile; use Help for onboarding and the guide. Ctrl+K finds a command without hunting through the groups.

Read the design around the tools

• The stage rail is Location · Crossings · Stations · Estimate. It controls geometry locking and prerequisites (Chapter 4).
• The left panel contains the active stage's schedules. In Location, plan points and grade points are editable; A marks values set automatically.
• Drawing tools, layers, basemap controls and scale stay beside the plan. They are view controls, separate from the task groups.
• The profile shows rail and ground levels, cut/fill, gradients and vertical curves. Curvature and cant share its chainage axis; mass haul can be opened below.
• The compliance orb opens findings from any stage. The status bar reports cursor coordinates, chainage and design values.

The three views

The plan, the profile and the curvature-and-cant diagram are three projections of one object and they stay registered with each other. Zooming the chainage in the profile zooms the curvature diagram with it; the plan keeps its own transform because it is the only one of the three in two spatial dimensions.

The empty workspace

Getting the width back

[, or the button at the end of the tab strip, folds the side panel down to its icons and gives the width to the views; any icon opens it again on that table. Shift+F gives the plan the whole window, using the browser's full-screen mode where it is allowed and filling the window where it is not, so it works inside an embedded frame too. Esc returns.

Why the geometry locks

Inside stage 2 the plan and profile carry a LOCKED badge and the handles stop dragging. That is not decoration: it is what stops a crossing schedule being invalidated by somebody nudging an intersection point. Every over-or-under decision in the schedule is a comparison of rail level against ground level at a particular place, and moving the line moves all of them. Going back to Location is therefore a deliberate act, and the schedule is recomputed when you return.

The gate

The gate is about prerequisites, not perfection. Four of the five conditions are hard: without an alignment, a grade line, a ground profile and a position on Earth, the second stage has nothing to compute from. The fifth — compliance — is deliberately soft, because preliminary work proceeds with warnings and often with known errors, and a tool that refuses to continue until every check is green is a tool that gets abandoned. Warnings never block.

The same process, in words

1. Say where the line has to go. Two ends and any number of obligatory points; the router is free between them and pinned at every one.
2. Say what kind of railway it is. Standard, design speed, slowest traffic, and the considerations that price the ground — what to avoid, what to serve, what a structure costs.
3. Say how well you want the ground known. The terrain grid is the single most consequential number in the run, because every bridge opening and every earthwork quantity is read off that surface.
4. Let it route, fit and repair. Ten seconds to a minute, with a running log.
5. Read the run report and the compliance report, and decide what to accept.
6. Look the line up against the world — roads, railways, watercourses, power lines — and settle every crossing.
7. Place the stations, and let the yards flatten the grade line where they land.
8. Price it, and read what the total is still missing.
9. Export the drawings, the schedules and the model.

Opening the wizard

Alignment → Design route, Design a route from the opening question, or Ctrl+K and type route.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

1. 1 Basemap: street map, satellite, topographic or terrain relief. (Blank in this figure — the machine that took it had no access to the tile servers.)
2. 2 The corridor. A and B are the ends; the dashed line and its label are the direct distance, not the route.
3. 3 Zoom, and the zoom level the tiles are being drawn at.
4. 4 Project name — printed on the report cover and used to name the file.
5. 5 Railway division — the zone and division the line belongs to.
6. 6 The route points, each with its resolved latitude and longitude. The ◎ button re-centres the map on it; ✕ removes it.
7. 7 Add an obligatory intermediate point — then click where it must go.
8. 8 Direct distance, updated as pins move.
9. 9 Design considerations — seven tabs of what the design is allowed to do (see below).
10. 10 The standard: IR-BG, IR-MG, EN 13803, AREMA, METRO or HSR.
11. 11 Design speed. This sets the minimum radius, the cant and the transition lengths.
12. 12 Slowest traffic — what cant excess is judged against. Capped at line speed, because above it, it is not slow traffic.
13. 13 Run it.
14. 14 The map's own instructions: drag a pin to move it, click the corridor to pin a point the route must pass through, right-click a pin to remove it.

The route points

A and B are the two ends. C, D, E … are intermediate points the line is obliged to pass through — the junction it has to meet, the gap it has to use, the town it has to serve. The router is free between them and pinned at every one; each leg is searched separately.

Every point can be given three ways:

Terrain detail — the number that matters

Terrain detail names the spacing of the elevation grid the route is designed against: 200 m (Draft), 120 m (Coarse), 60 m (Normal) or 30 m (Fine). Whichever you press is the grid you get. Nothing coarsens it behind you.

It matters because a coarse lattice does not merely smooth a feature — it aliases it. What you get back depends on where the feature happens to fall between nodes. An incised watercourse 15 m deep, swept across one grid cell, reads as:

The structures engine reads exactly this surface to decide that a bridge is needed and how big, so on a 200 m grid a small bridge opening is a lottery. Wide valleys were never the problem; the nalas are.

What the setting costs

Under the buttons is what the setting will actually cost for the corridor as laid out — the ground grid, the number of tiles, the peak memory and a rough time — recomputed as the points move. The setting that gives the best detail this corridor carries comfortably is ringed, and the note names it.

30 m is the floor worth offering: the source data is SRTM/ASTER-derived at roughly that spacing, and a finer grid would interpolate rather than reveal.

The design considerations

Seven tabs, reachable from the wizard and from Alignment → Considerations at any time. Changing a limit re-runs every check immediately.

What the run does, in order

1. Fetch the terrain. Public SRTM-derived tiles, about 30 m resolution, anywhere in the world, no API key — proxied through /api/dem because the tiles carry no CORS headers, and cached in IndexedDB so a second run on the same corridor fetches nothing.
2. Check for a line that is already there (Chapter 7).
3. Search for a corridor. A* over the elevation grid, one search per leg between obligatory points. The state is (cell, heading) rather than just cell, so turning can be priced.
4. Fit the geometry. Simplify the grid path to an IP polyline, give each IP the largest radius its neighbours leave room for, design cant and transitions, then run the repair engine until it is compliant.
5. Fit a grade line. Smooth the ground, clamp to the ruling gradient, simplify to VIPs, then shift the finished line bodily so cut balances fill.
6. Recommend structures. Classify the cut and fill into viaducts, tunnels, bridges at watercourses, embankments and cuttings, and estimate volumes.

Reading the result

1 2 3 4 5 6 7

1. 1 The run report: 58.15 km, 8 curves, 1 auto-repair, meets IR-BG, neither end ties in. Everything it did, and the one thing it could not.
2. 2 The intersection points the search produced, each with the radius, both transition lengths and the cant that were designed for it.
3. 3 The verdict: 0 errors, 12 warnings, 1 note. Warnings do not block.
4. 4 The STATION TIE-IN note, raised because no existing track data reached the router — so neither end of the line leaves or joins a station properly. It outlives the wizard that raised it.
5. 5 Two GRADE_COMP warnings: a 1.000% grade through a 1.63° curve, where compensation for curve resistance puts the limit at 0.935%. Each carries Fix, Why? and a mute.
6. 6 The grade line fitted to the ground, with every vertical curve labelled by length and radius.
7. 7 Length and outstanding findings, always on screen.

When the corridor is not viable

The router reports up front when a corridor cannot be built rather than emitting a profile that floats hundreds of metres off the ground. If the height to be climbed is more than the ruling gradient can deliver over the distance available, it says so and says how much development would be needed.

What survives the thinning

The grid path is thinned into an IP polyline, and thinning is exactly the step that could slide the route past a point you pinned. It does not: where an optional vertex crowds an obligatory one, the optional one goes, and the report names the IPs that were held.

Running it again

The wizard remembers the corridor, so re-running at another design speed or another terrain detail is a matter of changing one control and pressing Design the alignment again — and the terrain cache means the second run fetches nothing. Four runs at four speeds is the input to the speed–cost frontier in Chapter 13. Review → Compare → Compare options puts two of them side by side.

Where a railway already exists between the two points, it is the single most important fact about the corridor: the land beside it is already railway land, the crossings are already built, the gradients are already proven. A router that strikes out across country from A to B has thrown all of that away. So before any geometry is designed, the corridor is checked for a line that is already in it, and the run stops on a step called Checking for a line that is already there:

An existing connection exists: a single line (Nashik Road–Manmad) already runs between these two stations, 32.4 km of it. Doubling — a 2nd line is what a new line beside it would be.

Four questions, answered in order

The spacing

The default centre-to-centre spacing of the new running line is 5.30 m. The Indian Railways Schedule of Dimensions puts the obligatory minimum between the centres of adjacent straight running lines at 4.265 m, and new construction is not laid to the obligatory minimum; where traction masts stand between the tracks it goes to 6.0 m, and on curves it is widened again. The governing figure on any particular project is in that project's approved SOD and not in this program — which is why it is a field and not a constant. The takeoff at each end is laid at the same spacing, so the two agree where one hands over to the other.

What it cannot know

It also reads OpenStreetMap, which is contributed data: tracks is often absent, sidings are often untagged, and a traced curve carries a few metres of noise. The curvature figures are a screening pass, not a survey.

And it does not choose the side for the right reasons. Both sides are scored against the standing water, built-up land and quarries the router already avoids, because at this stage that is the only thing distinguishing them. What decides it on a real doubling is which side the station buildings are on, which side the land is already acquired, and where the level crossings and traction masts are — none of which is visible here. So the side is a default, offered with both scores, and overridable in Design considerations → Inclusion → Multiple Tracking.

When the track data does not arrive

The takeoff is the only thing tying a new line to what is already built, and it needs the existing track from /api/features. When that lookup does not answer there is no takeoff, and what comes back is a straight line from pin to pin that leaves one station across its yard and meets the next at whatever angle the corridor took. That is wrong in a way the plan does not show, so it is never silent: the router reports both ends as untied, the corridor lookup is asked a second time before it is believed, and the alignment carries a STATION TIE-IN warning in the checks pane that outlives the wizard it was designed in. It is the warning visible in Figure 6.5, and it is there because the machine that took the screenshot had no route to the map servers.

An empty answer and an unanswered lookup are told apart, because they are different claims. No railway mapped near either end is a fact about the ground. A lookup that never answered has not made a claim at all, and the route should be designed again once it does.

What is kept with the project

Whether the alignment is a doubling, a third line or a new corridor; which side of the existing formation it runs on and at what spacing; how much of it is parallel and how much is new geometry; the tightest existing curve and what speed it holds; and every stretch, with the reason it left the formation. It is written into the saved file because it is evidence rather than derivation — the OpenStreetMap extract it was read from is not saved and will have moved on by the time the project is reopened, and a line that cannot say why it is where it is would be indistinguishable from a greenfield alignment that happens to run parallel.

The horizontal alignment

An alignment in plan is an IP polyline: a start, a chain of intersection points, and an end. Each intersection point carries a radius and two transition lengths, and the solver turns that into a continuous chain of straights, clothoid transitions and circular arcs. Drag any point in the plan and the whole chain re-solves as you move.

+ IP inserts after the selected row; Delete removes the selected point; double-clicking empty space in the plan inserts an intersection point there. Tab and Shift+Tab walk the points, and ↑/↓ in a numeric cell steps the value — ten steps with Shift.

Right-click the plan or the profile for a menu of what can be done where you clicked: add a point there, or select, move or delete the one under the pointer. To work on several at once, Ctrl-click (⌘ on a Mac) puts a point into the selection or takes it out, and a right-drag draws a box that selects every point inside it — with Ctrl held, adding to what is already selected. A group then behaves as one: drag any point of it and the rest follow, keeping their shape; Move on the menu picks the points up so they follow the pointer until a click puts them down, and Esc puts them back; Delete removes the lot in one step that one Ctrl+Z undoes, keeping the two end points, which are where the line starts and stops. In the profile a group stops a metre short of the first VIP outside it, and Shift holds every chainage in it. While the geometry is locked the menu still opens, and says why nothing in it can move a point.

The profile's menu adds two things of its own. Edit level on a VIP — or a double-click on it — opens a small form at the pointer with the VIP's level and the gradients in and out, each typed as 1 in n, as a percentage with %, or as level; whichever is typed, only that VIP moves. Edit grade on empty profile — or a double-click on a gradient's label — opens that gradient and the level at either end, and Keep says which end stays where it is when the gradient is typed. The profile follows as you type; Enter keeps the change as one edit and Esc puts it back, and a gradient steeper than its leg may carry is named in the form before it is kept. The Grade out column of the VIP table takes a gradient typed the same way and moves the next VIP to it.

Regrade to the ground, on the menu of a VIP or of a selection, chooses those VIPs' levels as close to the ground as the ruling gradient lets them be, keeping every chainage. Every gradient it changes is held to its leg's own limit: the ruling gradient of its gradient section, less the compensation of any curve on it, and 1 in 1200 through a station yard. The VIPs either side stay where they are unless a gradient to them would otherwise break that limit; then they move by no more than they have to, and the change stops where it runs out. The ends of the profile, a VIP in a station yard and a VIP whose level is locked are never moved unless they were selected too. A curve the steeper change of grade has outgrown is lengthened with it, and the whole regrade is one edit that one Ctrl+Z undoes.

The vertical alignment

Drag a VIP in the profile to reshape the grade line, holding Shift to change the level without the chainage. Shift+wheel changes the vertical exaggeration, which is stated on the drawing so that a 25× picture is never mistaken for the shape of the railway.

Double-click empty space in the profile to add a grade break, the way double-clicking empty plan space adds an intersection point. It goes in at the chainage and level you clicked, in the leg it landed in; click within a few pixels of the grade line and it takes the rail's own level, so the break is a place to bend the profile from rather than a step in it. The vertical curve it arrives with is sized to the room between its neighbours — a break dropped into a short leg carries a short curve instead of a 400 m one that would overlap the curves either side of it before you had touched anything. + VIP does the same in the middle of the selected leg, and Delete removes the selected break. This is how a line is developed in hill country: the grade line is bent to reach down to the ground where the ground can be met, rather than held straight over it and carried on structure.

How far one gradient may run

Max length of one gradient, on Considerations → Design Limits, caps how far the profile may go without a break in it. It ships at 5 000 m on every standard. Its opposite number, the minimum length, is there to stop a train surging between grade changes that come too fast; this one is there for the other failure, and it is the one that costs money in hill country.

A grade line is simplified by deviation, and deviation alone does not care how far it travels: on ground that stays near enough to straight it will return one gradient seventeen kilometres long. Two things are wrong with that. A locomotive on an unbroken pull is working at its continuous rating for the whole of it. And nearly straight is not straight — the metres the simplification called negligible are metres the finished line stands off the ground, and past the crossover depths what holds it off the ground is viaduct and tunnel. Breaking the gradient lets the profile come back down to ground it can actually reach.

Designing a route applies the limit: the router divides an over-long gradient into as few pieces as the cap needs, evenly spaced, and snaps each break to where the chosen grade line bends hardest within its division — so the break develops the line rather than just subdividing it. On the plateau sample this takes the longest sustained pull from 19.3 km to 6.3 km for three extra vertical points. On an alignment you are editing by hand, add the break yourself by double-clicking the profile where you want it.

The ground profile

A route designed from the map arrives with its ground profile already sampled from the terrain grid. An alignment drawn by hand needs one: paste or load chainage, level rows in the Profile tab. That gives cut and fill shading, a cut/fill column in the setting-out table, and the terrain rules in the compliance engine something to measure against. Without it the terrain rules stay quiet rather than guessing.

Putting the drawing on the Earth

Basemap tiles, corridor lookups and every export that carries a coordinate need the project to say where on the earth its plane sits. A route from Design a route already knows. For an alignment drawn by hand, pick a point in the Plan tab — the grid origin, or any intersection point — and give its latitude and longitude, in decimal degrees or as 27 10 30 N, 78 02 31 E. The georeference is saved with the project.

Drawing on the plan

Beyond the computed alignment, the plan takes manual drafting for constraints and context. Shapes live on layers with specific meaning rather than being lines on a screen, and they are drawn in map space, so they move with the terrain and not with the viewport.

Each avoidance area can carry a setback in metres and an outer regulated belt, because the statute that constrains an alignment is written that way: the AMASR Act bars construction within 100 m of a protected monument and regulates the next 200 m. Presets for the usual instruments — AMASR, wildlife, forest, CRZ, defence — fill in the distance, the authority and the class.

Re-designing after a change

Redesign runs the whole automatic pass again over the current considerations — radii, cant, transitions, grade line, the outstanding checks, and the station yards that sit on the geometry — as a single undo step, and then says what it did rather than reporting a number. If nothing would change it says so instead of pretending to work.

The checks at the end of it are the same pass Fix all runs, with the same corridor behind them where one has been looked up. The pass can adjust the actual railway alignment towards a more perpendicular crossing and seek the rail level that clears the road. New bridge proposals have square supports; the measured obstacle angle remains separate. A crossing whose full opening or approach arrangement has not been established stays unresolved.

It respects the areas you have drawn. Easing a radius moves the arc away from its intersection point, so a curve widened for a higher speed cuts the corner more deeply than the one it replaces and can land on ground the old one cleared. Where that ground is marked prohibited, the widening stops at the last radius that stays clear: the router bars its search from those cells rather than pricing them, and a rebuild that walked in afterwards would be reversing that decision on the drawing. The same bound applies to every repair in the pass behind it, including the one that would read the held curve as sub-minimum and ease it straight back in.

A held curve is a real conflict, not a solved problem, and it is reported as one: the redesign names the curve, the radius it stands at and the area that held it, and the compliance list goes on reporting the radius as below the minimum for the speed. Something has to give — the route, the design speed, or the outline — and which of the three is not the tool's decision.

A weighted or regulated area is a price or a consent rather than a barrier, so a curve may be eased across one exactly as the router may route across one. What you get there is the sentence, not the refusal: the redesign says how many metres of line it has put inside which area, at the top of the report, rather than leaving a fresh finding on the Checks tab for you to discover later and attribute to nothing. The same note appears where the redesign has taken the line back out of an include area it was drawn to pick up.

An include area you have ticked as one the line must pass through is treated like a prohibited one, the other way round: a curve is not widened so far that the line leaves it, and no repair after the rebuild may take the line out of it. The report names the curve and the area, and the curve is reported as below the minimum radius until the route, the speed or the outline changes.

Why a curve has a curve at each end

Curvature and cant have to rise together, or the resultant force swings out of the plane of the track while the train is still on the transition. The clothoid — the Euler spiral — is the curve whose curvature increases linearly with distance travelled:

1/r(l) = l / A²,        A² = R · Ls
θ(l)   = l² / (2A²)
x(l)   = ∫ cos θ ds,    y(l) = ∫ sin θ ds

so a linear cant ramp along a clothoid keeps the two in step throughout. The integrals are evaluated by series expansion in θ, which for railway spirals (θ well under 0.25 rad) is exact to about one part in 10¹², with Simpson quadrature as a fallback for pathological cases — and as the independent reference the test suite checks the series against.

Cant, deficiency and excess

Cant follows the standard relation, parameterised by the dynamic gauge G so that one equation covers every track gauge:

C = G · V² / (127 · R)      [mm]     V km/h, R m, G mm

G = 1750 mm  →  the Indian Railways form   C = 13.76 V² / R
G = 1500 mm  →  the standard-gauge form    C = 11.81 V² / R

How long the transition has to be

Transition length follows from the cant by the three usual criteria, and the longest wins:

The vertical alignment

Reading the two together

What is not modelled

• Simple curves only. One radius per intersection point; compound and reversing curves at a single IP are not modelled. A reverse curve is built as two IPs, which is the normal way to do it anyway.
• Clothoid transitions only. No cubic parabola, sinusoidal or Bloss transitions.
• Parabolic vertical curves only, as above.
• One running line at a time. Multiple tracking lays a new line beside an existing formation, but a doubling is still one centre line: the second track is not designed as its own alignment with its own geometry.

The panel

1 2 3 4 5 6 7 8

1. 1 The verdict, in three numbers. Errors break the standard's exceptional limit; warnings sit between the normal and exceptional limits, or flag desirable practice; notes are neither.
2. 2 Filter by code, chainage or a word from the message; the strictness selector; and group, which sorts forty findings into the profile is the problem rather than a wall of text. A report of more than three hundred findings — which a long line with no ground profile easily reaches — draws the worst three hundred and says so; the filter box is how the rest are reached.
3. 3 Fix all — apply every repair that can be applied, in one pass. It runs in slices so the page stays usable, reports progress on a card at the bottom left with a Stop on it, and comes back after forty-five seconds whether it has finished or not; whatever it repaired stands as one undo, and pressing it again carries on. It will not run while a variant is in use, because the findings are then indexed against the line on screen and the points belong to the base alignment.
4. 4 A finding. Title, plain-English measurement, and — in the monospace line — the code, the chainage, and the measured value against the limit.
5. 5 Per-finding actions: Fix applies the repair, Why? opens the rule behind it, and ⊘ mutes that rule for this project.
6. 6 A second finding on the same curve, from a different rule. Repairs interact, which is why Fix all re-solves between them.
7. 7 The curve annotation the plan draws for every curve: radius, transition length, cant, deflection angle and hand.
8. 8 The stage gate, which this project fails on two hard conditions — it has no ground profile and no position on Earth, so the terrain rules stay quiet and stage 2 is out of reach.

Fix all revisits a blocked repair when another change makes it possible, then tries coordinated curve, profile and station adjustments. It preserves the project's design requirements, fixed points and movement bounds, and keeps the best checked result. Remaining findings stay visible.

For an unresolved crossing, use Make it fit in the crossings panel. It searches local adjustments and coordinated profiles, including approach ramps and station yards. A result is applied only when the selected crossing fits without worsening a hard compliance failure or breaking a crossing that already fits. The chosen structure is preserved. Progress and Stop appear during the search; stopping or failing to find a verified fit leaves the design unchanged. A successful fit is one undo.

What a finding contains

Take the first horizontal error in Figure 10.1, as it reads on screen:

Radius below the minimum for the design speed. IP1: radius 600.000 m is below the absolute minimum 696.229 m for 120 km/h. Maximum speed here is 110 km/h.
R_MIN · 0+816.1 · 600.00 vs 696.23 m

and the one below it, which is the more instructive of the two:

Radius cannot serve both speeds. IP1: radius 600.000 m cannot serve both 120 and 50 km/h. The fast train needs at least 231 mm of cant and the slow one tolerates at most 132 mm — no value at the 5 mm setting-out step satisfies both. Ease the radius to 964.567 m …

Repair

Each repair explains itself in the language of the decision it took:

Eased IP1 from 600 m to 975 m — below that no single cant can serve both 120 and 50 km/h.

Where only a change of route or design speed would resolve something, the engine declines and explains the trade-off instead. Those are design decisions, not the tool's to make:

IP1 and IP2 are 608 m apart, but at 120 km/h the minimum radius is 965 m and two such curves need about 960 m between them. Your options: move the two points at least 352 m further apart; drop the design speed to about 95 km/h; remove one of the two intersection points.

Severity is yours to set

One broken rule does not blank the report

Each group of checks runs inside its own guard. A rule that throws on a degenerate geometry reports itself as RULE_ERROR, naming the group that failed, and the rest of the report stands. The test suite verifies this by making a rule throw on purpose.

What is checked, and when

Twelve categories, with reference codes in Chapter 19. The terrain rules only run when a ground profile has been loaded or generated; without one there is nothing to measure against and the engine stays quiet rather than guessing. The crossing and station rules likewise wait for stage 2 and stage 3 to have produced something to check.

Looking the corridor up

Roads, railways, watercourses, land use, power lines and pipelines come from OpenStreetMap by way of Overpass, through /api/features. It is a server route rather than a fetch from the page for two reasons: Overpass is slow, rate-limited and periodically down, so extracts are cached in Postgres keyed by a normalised bounding box; and the cache is written with a key that must never reach a browser.

The over-or-under decision

The decision is one comparison. With d as rail level minus ground level at the intersection, a road passes under when d ≥ headroom + deck, and over when −d ≥ clearance + deck. Between those, both ways out are quoted rather than the tool refusing to answer.

Any of them can be set by hand. The override is respected and the engine keeps its own opinion beside it — but whether the chosen type actually fits is still measured, and a forced type that does not fit is a compliance error. A vertical shortfall may be addressed by changing the grade line; a missing square opening, approach or hydraulic arrangement needs its own resolution.

Waterways

Design a bridge in its own workspace

Open Structures, choose a saved bridge or an eligible crossing in the bridge selector, then choose Workspace. Structures → New bridge starts a manual bridge. A crossing card's Design bridge… and a proposed viaduct's Design viaduct… open the same editor. The main bridge command uses the Crossings stage prerequisites; satisfy the alignment, grade, ground and georeference requirements first.

1. Open Bridge settings. Check the centre chainage, carried axis, structure type, carried level, ground/bed level, actual crossing obliquity and recorded hydraulic evidence before adjusting members.
2. In Design, select a span or support in the component tree. Set the span family and length, pier/abutment dimensions, caps, bearings and foundation arrangement. Spans can differ; at least one span remains. Each span boundary has a support.
3. Inspect the linked plan, longitudinal elevation and transverse section. Click an individual member or use its detail list to inspect parts hidden behind others. Yellow handles change span lengths; purple pier handles redistribute spans while retaining total length. Select a support or enter a section offset to inspect the cut there.
4. Add protection and approach components, then inspect them in Simulation and the A1 drawing preview. Work through Review findings and record the drawing references actually checked for this project.
5. Choose Apply bridge to update the working project, or Save project to apply and save it to its normal destination. Check the main save indicator for completion.

The five tool groups are Design, Drawings, Simulation, Review and Export. Switching groups keeps the draft. The alignment overview locates the structure on the corridor; schematic mode works without imagery, while street or satellite backgrounds need a project georeference and reachable tile service. Undo and redo inside the editor affect its draft. Applying the bridge creates one undo step in the main project. Closing a changed draft offers apply, discard or continued editing.

Choose the steel family and floor arrangement

Select a span and set Superstructure. The steel families have different members and load paths; changing the family installs its preliminary dimensions and resets that span's individual member overrides. Review the resulting dimensions and quantities.

For a through family, Track floor arrangement offers Open deck · sleepers on stringers or Ballasted RCC deck · requires adopted floor design. An open deck has no generated concrete deck slab or ballast bed. A ballasted floor adds geometry and quantities; it does not check the extra dead load or make the main trusses composite. Composite plate girders retain their RCC deck.

Set Outer girder centre spacing from the adopted arrangement. For a railway carried between side girders, also set Required track clearance width and Required track / OHE clearance above rail. The section and A1 GAD show the rectangular envelope, and Review reports obstructing members. The initial 4.8 m × 7.0 m envelope is an editable planning assumption. Verify it against the project's Schedule of Dimensions, OHE, cant, vehicle movement and curve requirements; it is not an approved swept vehicle envelope.

The family defaults and depicted connector pattern are conceptual. They do not reproduce an authenticated RDSO standard drawing or a complete fabrication schedule. In particular, composite construction stages, shear connectors, member capacity, fatigue and rail–structure interaction still require the applicable design calculations. A road bowstring arrangement has no dedicated component family and remains unresolved in this editor; a through-plate placeholder does not establish that bowstring's geometry.

Keep square supports separate from the obstacle angle

New automatic arrangements use square support lines. In Bridge settings, Structural support skew (degrees) is separate from Crossing obliquity from square (degrees). The latter describes the actual river, road or railway. Keep this evidence: making supports square does not straighten the obstacle or remove its extra opening length.

A square span must cover the obstacle at both deck edges. For a straight corridor of normal width W, carried width D and acute intersection angle a, its longitudinal envelope is W/sin(a) + D·|cot(a)|, before support setbacks and other allowances. A mapped width already measured along the railway is not divided by sin(a) again. For example, a 30 m corridor crossed at 60° occupies about 34.64 m at the centreline and 39.17 m across a 7.85 m-wide deck.

Proposals extend a square span where an available arrangement can cover that envelope. The crossing stays unresolved when the span is insufficient, the crossing is nearly parallel, or the surveyed layout is missing. Oblique culverts need inlet/outlet and barrel arrangements; oblique multi-pier waterways need flow-aligned piers and independent obstruction, afflux and scour checks. Overline water structures and rail-under-rail arrangements need their own surveyed square layout and approaches. Change the actual alignment or crossing location, or develop the missing arrangement; a change to an angle field is not a site solution.

Older saved bridges retain their structural skew. Use square support lines changes those supports while retaining crossing obliquity. Inspect support positions, the complete opening, foundations and hydraulic evidence before applying. Square bearing lines alone do not establish a suitable river-pier orientation.

Levels, foundations and box cells

Foundation choices include open footings, pile groups and caps, and wells. For piles, the pile-cap base RL and pile length define the toe. For wells, the foundation base RL is the top of the sinking section and its depth defines the bottom. An individual member's Z override is an absolute centre RL; it is different from an ancillary wall's datum-relative base. Reset this detail restores the generated member. Check connections after overriding a member's length or position.

For a box, Barrel length (m) is the transverse passage or flow length. It is separate from the cell wall centre spacing, clear height and wall thickness. Bridge settings can set it across all cells; a selected cell can differ. Clear openings exclude the cell walls, so increasing wall thickness changes the effective waterway. Check the actual bank section against the illustrative earth cover shown over a buried box.

Wing walls, return walls and their footings

Add a wing or return wall from the ancillary components. Choose its abutment or box-mouth anchor, end and side, then its ground/bed/carried-level datum, offsets, plan angle and material. A wing wall splays away from the opening; a return wall follows the retained approach. Anchored walls follow span and barrel resizing. An explicit abutment wall replaces the generated wing at that corner rather than adding a second wall over it.

1. Set Stem thickness, Root stem height and Tip stem height. The wall top joins the root and tip; inspect the elevation to confirm the intended taper.
2. Set Wall footing width and Wall footing depth. The separate footing lies below the stem; inspect a root section to check the projection and levels.
3. Duplicate to the opposite side or end as needed, then check each anchor and plan angle. Review joins to the abutment, approach slope, pitching, apron and drainage.

The editor also includes approach slabs, walkways, parapets, drains, pitching, aprons and filters. Their dimensions describe preliminary geometry; a drain envelope does not establish hydraulic capacity, and a wall with a footing has not passed sliding, overturning, bearing or reinforcement checks.

Review after a route, hydraulic or member-model change

A saved bridge remains when the route or hydrology is recalculated. Changed source chainage, ground/rail levels, crossing angle or hydraulic evidence produce a review notice. Refresh location and crossing evidence adopts the current crossing location, obliquity and requirements while keeping component dimensions and structural support skew; review the carried RL and foundations afterwards. A bridge whose original crossing disappeared remains saved with a finding. It is not silently deleted or redesigned.

Older bridge documents show a separate notice for the corrected member model. Their explicit dimensions remain; through-family spans without a saved floor choice retain the previous ballasted-floor intention. Review the members, obsolete member overrides, floor choice, clearances and changed quantities. Apply bridge accepts the current geometry model for that design. Existing detailed-estimate items remain separate snapshots: review and update or re-import their quantities deliberately, checking for duplicate items.

The review checks geometry, support arrangement, opening, track clearance, recorded flood clearance and foundation depth. In RDSO drawing and design review, record the engineer's adopted drawing number, revision and source URL after checking the original document. Complete Adopted railway loading, Adopted track arrangement and Construction / erection method from that design basis. Legacy recommendation labels are unverified review aids. Entering an adopted reference does not certify RDSO compliance.

In Simulation, use cutaway/transparency to inspect buried members, component opacity and exploded separation to inspect overlaps, and the recorded HFL water plane to inspect levels. Assembly progression reveals geometry in generation order; it is not a construction programme. The moving train is a visualisation, not a moving-load or capacity calculation.

Preview and export an A1 general arrangement

Open the workspace's A1 GAD preview or Export group. Check the plan, longitudinal elevation, typical span section, support/foundation section, span dimensions, chainages, RL references, schedules, notes and title block before downloading. Wing and return walls have W1–Wn schedule identifiers and dedicated root/profile details where required. Sections cut the actual resolved members; concealed edges are dashed and centrelines use long-short lines.

Choose A1 GAD PDF or A1 general arrangement DXF in the workspace. Output → Export deliverables → Bridge GAD sheets packages saved bridges and current proposals and can produce a PDF of all bridges. Individual drawing SVGs, component/quantity CSV and bridge JSON backup/import are also available. Engineering downloads use the deliverables access policy; previews and working-file backups remain available with the design tools.

A1 landscape is 841 × 594 mm; print the exported PDF at 100% / actual size. Plan and elevation share a stated scale; details can use different stated scales. Sheet geometry and written dimensions are in millimetres, with chainages and RLs in metres as labelled. Do not infer a ground distance from the screen preview's size.

Applied bridge components feed the generated bridge quantities and replace that bridge's default cost. A detailed estimate is a separate fixed bill: apply a bridge before importing a design snapshot, and revise the bill deliberately after later bridge changes.

Power lines and pipelines

The corridor query asks for transmission lines and pipelines too, and the clearance is measured over an overhead contact wire that is already 5.5 m up — so a line that comfortably cleared the road it was strung over may be nowhere near clearing an electrified railway. It is re-checked every time the grade line moves.

When a layer does not arrive

Nothing in an Overpass response separates no watercourses in this corridor from a mirror that is misconfigured or half way through a reload: both are a 200 with an empty element list, and an empty corridor is legitimate. A second mirror can tell them apart, so an empty answer is put to the next mirror before it is believed, and a mirror that finds the river overrules the one that did not.

Look up again sends fresh=1, which goes straight past the cache — kept for a season, one wrong no rivers here would take the bridges out of every schedule through that cell.

The yard editor

Pick a station and the editor sets out the running lines and everything that goes with them:

Working the drawing

The editor is laid out like a drawing tool made for this one trade. The objects are down the left, grouped as track and junctions, station and depot, buildings, and site; drag one onto the drawing, or click it and then click where it goes, and it lands in the nearest place the section can hold it. Beside them a Layers tab turns each layer off, solos one so it can be read on its own with the rest ghosted behind it, or locks it so it stays drawn but cannot be picked. The properties of whatever is selected are down the right, grouped as general, geometry and design.

Add parallel track — from the library, from a right-click on a road, or with P — lays a road immediately outside another at a track centre you state. A road given its own track centre is held to it and to the 5.30 m SOD minimum rather than to the yard's plain centre, so a yard road at 5.30 m is a design, and one at 4.20 m is a conflict drawn on the drawing where it is. Every turnout is numbered along the yard, T-1 onwards, and clicking one shows its hand, its toe and fouling-mark chainages, its lead and lead radius, the crossing angle, and the speed its route may be taken at.

Under the drawing, the Checks tab lists every conflict and takes you to the thing at fault when you click it; the Longitudinal Profile draws the rail level and the ground over the whole yard, with the yard limits the 1 in 400 rule is measured over; and the Cross Section cuts square across the yard wherever the chainage probe was last used, with offsets to scale and the track centres dimensioned. A summary beside them gives the yard in figures. Generate yard takes a brief — loops, platforms, the longest train, depot lines — and lays out candidate yards side by side, each solved and checked, to start from.

The throat is a ladder

Plateau grading

A yard cannot sit on a steep gradient. The vertical alignment is checked and flattened into a yard plateau at a maximum of 1 in 400 (0.25%), inserting vertical curves to tie it back to the ruling grade — which is what the Indian Railways Schedule of Dimensions requires. This is why entering stage 3 changes the profile: the plateau is real geometry, in the same VIP list as everything else, and it will show up in the setting-out table and in the earthwork.

Signals, and the station limits

The signalling follows from the throat once it is laid: the home an adequate distance outside the first points, a starter on each running line at its fouling mark, and the advanced starter beyond the last points, where the block section begins. The distance between them is what each running line can berth — and a loop too short to hold the train the line is planned for is reported with both figures, and lengthened for you.

What comes out of it

The finalised layout drops straight into the DXF export, so the 5 km sheet packages carry fully modelled station limits on standard CAD layers rather than a centre line. The signalling and interlocking schedule comes out beside it as a CSV and as a sheet of the workbook: every point with its number and how it is worked, every signal with what it reads over, the berthing lengths, and the equipment the standard of interlocking asks for.

Start a detailed estimate · Enter measurements · Select rates · Apply, save and export

The generated design estimate

The estimate schedule in Stage 4 prices quantities from the current geometry, structures, crossings and stations. Its missing-work checklist applies while the generated estimate is the active cost source. A detailed bill has its own item and rate review instead.

The general abstract

Twenty-six plan heads are offered on the selector — new lines, gauge conversion, doubling, traffic facilities, road safety works, track renewals, electrification and the rest — so the abstract can be classified under the head the work is actually being sanctioned against.

Start a detailed estimate

Open Output › Detailed estimate, or press Detailed estimate… in the estimate panel. This workspace can be opened without completing the alignment stage gates; a stand-alone bridge, building or other component bill does not need a routed corridor.

1. For a new bill, use Start blank estimate or add the first component. For a bill based on the alignment, choose Import current design.
2. Open Basis & charges. Check the estimate title, project railway zone, location and adopted rate authority before choosing rates.
3. Choose a Component head and + Add component. Rename it for the actual work package: for example, “Bridge 14 — foundations” or “Station A — platform works”. Enter its reference code and scope notes.
4. In Component bill, use Add schedule item for a published catalogue entry or Add custom item for work with a project rate or analysis.
5. Complete quantities and rate evidence, check Review, then apply and save as described below.

Use separate components for packages you need to issue independently. Assign the correct railway head, especially Land and Preliminary expenses, because charge exclusions follow that classification. Include component and each item's include control let you retain an option without adding it to the total. Excluding a record preserves its data; deleting it removes it from this draft.

Enter billing quantities and measurements

Select an item in the bill to open its details. With no measurement rows, Quantity is the quantity in the displayed billing unit. Once measurement rows exist, those rows determine the quantity and direct entry is disabled. Remove the measurement rows to return to direct entry; check the resulting quantity before proceeding.

1. Press Add measurement. Give the row a description that can be checked against a drawing, chainage range or site record.
2. Enter number, length, breadth and depth. A row measures number × length × breadth × depth. Enter 1 for a dimension that does not apply.
3. Choose addition or deduction. Deduction rows subtract openings, voids or other excluded work from the measured total; retain their descriptions.
4. Set the Measurement divisor to convert the measured total to the published billing unit. The displayed bill quantity is net measured quantity ÷ divisor.

Changing the unit label alone does not convert a quantity or rate. Check conversions between kg and tonnes, per-unit and per-hundred rates, and compound units such as tonne-kilometres. Record measurement units and assumptions in the item notes. Replacing an item with a catalogue rate in a different unit asks to clear its existing quantities and measurements; re-enter them on the new basis.

A blank quantity or rate means Unpriced, not zero-cost work. A genuine zero is retained as zero. Negative published rates can represent credits; check the combined signs of any credit rate and deduction quantity. Invalid number text stays visible and prevents Apply or export until corrected, including invalid entries in another component.

Choose schedule rates and record the local basis

The Rate library holds 4,249 extracted item variants: 1,065 from Central Railway USSOR 2021 and 3,184 from CPWD DSR 2023. Search by item code or description; filter by schedule and chapter. Check the selected row's scope, unit, rate and variant before adding it. Carriage lead bands are separate variants, not interchangeable prices for the same movement.

Selected rows keep the published item code, unit and rate, source document, and available page or volume references in the project. Reopening the file uses that saved rate snapshot; it does not silently substitute a newly fetched price. Follow the source link to verify inclusions, exclusions, lead conditions and applicable correction slips.

Ambiguous units or incomplete source descriptions remain review findings. For example, a row with an unnamed thousand-unit basis must be checked against the original schedule before its quantity is entered. Most DSR entries record a volume rather than a page. Carriage coverage is partial. Use a sourced custom item for a missing entry and for specialist electrical or signalling work outside these civil schedules. See Appendix B for source links and extraction limits.

To adopt a different project price, select Project / quoted rate, enter the adopted value and record its authority in the notes. Keep the original schedule reference as evidence where useful. A schedule item's published-rate field is not a place to disguise an unrecorded override.

Build an analysed rate

1. Add a custom item, enter its description, billing unit and quantity, and select Rate analysis as the rate type.
2. Add constituent lines for material, labour, plant or subcontract work. Each line carries a description, coefficient quantity, unit, adopted rate and source. Coefficients are the resources needed for one billing unit of the finished item.
3. Enter overhead and profit percentages explicitly. The analysis sums constituent costs, applies overhead, then profit. Review the resulting adopted unit rate against the scope.
4. Record leads, lifts, wastage, tax treatment and anything else included in that rate. Imported reference analyses remain provisional until you review them and choose Analysis.

For example, a constituent subtotal of ₹1,000 with 5% overhead and 10% profit gives 1,000 × 1.05 × 1.10 = ₹1,155 per billing unit. Project and analysed rates are already adopted prices; neither is automatically multiplied by the USSOR or DSR index.

Cash, stores and project charges

Enter an item's Stores share (%) to allocate its amount between stores and cash. A 25% stores share on ₹1,000 gives ₹250 stores and ₹750 cash; it does not add ₹250 to the item price. The combined summary adds included components and applies project charges once.

Item amounts, stores allocations and payable charges are rounded to paise; summaries add those rounded amounts. Set a charge to zero when it is not applicable or is already included in your adopted price. Review the stated bases against the sanction and contract requirements.

Review, apply, save and export

Open Review before issue. Select a finding to reach the relevant component, item or basis field. Missing quantities or rates are excluded from the priced subtotal and remain flagged. Provisional allowances can contribute money but still need review. Local-rate and source warnings are not resolved merely because all arithmetic cells contain numbers.

Use Excel workbook or Combined CSV for the full draft, and Component Excel / Component CSV for the selected component. Exports use the current draft; exporting does not apply it or save the project. Engineering downloads follow the site's Pro deliverables access policy. Review-mode and visitor projects cannot apply edits; return to the base alignment before editing a project with an active variant.

The Excel workbook contains the general, head and component summaries; individual component bills; measurements; rate analyses; pinned source rates; settings; and review findings. Editable input cells feed live formulas, with calculated results supplied for viewers that do not recalculate. CSV carries the item register and summary; it is not the measurement and formula workbook, nor a replacement for the project file.

With a detailed bill active, the full project workbook and cost-estimate export carry its sheets. The DPR identifies components by their saved names and heads, includes GST when applied, and marks incomplete totals as priced subtotals. Custom component names do not establish depreciation lives; classify the assets before completing the report's terminal value calculation. Recheck report quantities and bill scope after any design change.

What it costs to own, not only to build

A first cost is the number a comparison table has always carried, and on its own it points at the wrong corridor with some regularity: a shorter route through the hills is cheaper to build, and then trains climb its ruling gradient every day for sixty years. Four engines address that, all reachable from the Workbench.

1 2 3 4 5

1. 1 The engines, grouped: cost, ground, corridor, review.
2. 2 needs input — the panel is listed but cannot run yet, and opening it says what would make it run.
3. 3 A panel that can run against this project.
4. 4 The verdict, in a sentence, before any table.
5. 5 The table, reach by reach, with the units and the source of every figure.

The engines

Importing a survey

Points, a schedule of cross-sections, LandXML from a total station, or an ASCII grid — the format is worked out from the file. What the panel reports is not 4,812 points loaded but the coverage: which reaches of the line the survey actually covers, and what the volumes over the rest are still worth.

The polish pass

optimise.js asks whether the design could be better, which nothing else in the chain does. Five objectives — cost, earthwork, balance, running time, traction energy — minimised by a hill climb that never accepts a candidate introducing a compliance error. Never a penalty: there is no exchange rate between breaking the standard and saving four crore. It produces a trace that names every move and can be rewound to any step on it, because a design that improved for reasons nobody can name is not a design anybody will sign.

Asking in words

Tools → Ask handles supported requests locally first, using the current project, application guidance and engineering engines. Local answers make no AI calls and need no AI key. Ask identifies its sources and reports missing inputs.

Inspect an alignment, explain a finding, review cost or quantity results, or prepare a supported change. Review the proposal's target and parameters, then choose Apply change. Accepted edits use normal undo. Invalid inputs, read-only projects and stale proposals are refused. Unsupported edits open the relevant workspace for you to finish; opening it is not a completed design change.

Automatic Gemini fallback is on by default. For requests the local resolver cannot handle, the question, relevant conversation and project/tool context pass through this site's /api/assistant to Gemini. Ask settings can disable fallback, set the Gemini model or hold an optional personal Gemini key. An empty key field uses the site's configured key. Both paths require sign-in and use the same server route.

Conversations and personal keys stay in this browser, separately from project files, and can be cleared in Ask. They do not follow a file to another device. Map/source lookups and cloud saves retain their own network requirements when Gemini fallback is off.

Cab ride 2: inspect the corridor in 3D

With Pro, open Review → 3D & cab rides → Cab ride 2 (3D) after an alignment is present. This is the newer 3D renderer, with modelled station scenery, trees and buildings. The original Cab ride remains a free, separate view and is documented below; its three-camera controls and rendering limitations do not describe Cab ride 2.

1. Start in Cab, use the chainage control to reach the area under review, and play or pause the ride. The running information relates to the current alignment.
2. Change to Chase to see the train and track ahead, Orbit to inspect slopes and structures from the side, or Lineside for a view beside the railway. Keys 1–4 select those four cameras.
3. Use the Now, Trip, Ride, Stations and Findings panels to relate the picture to chainage, grade, cant, station locations and reported checks. Inspect a station from both ends and from Orbit before interpreting a single cab frame.
4. If scenery looks out of place, check the saved station, bridge and section parameters first. Reopen the ride after applying changes. A plausible picture does not close an engineering finding or add a missing bill item.

Reading the stations

Platforms follow the station schedule, their declared ends and the grade of the line. Pitched shelters use visible steel rafters, purlins, roof sheets, gutters and downpipes. Footbridges include trusses, cross girders, bracing, foundations, covered stairs and landings. Stair access is kept clear of shelters and furniture. Short or narrow platforms omit facilities that do not fit, rather than forcing a full-size layout into the space.

Yellow station boards sit near platform ends and face the tracks; supplied local-language and Hindi names can appear alongside the main name. Benches, bins, drinking-water points, tactile strips and lighting provide context. The station building has windows, verandah and circulation spaces. These are procedural visual details, not a survey of an existing station or a complete building, accessibility or fire-safety design. An explicitly empty footbridge schedule draws none; illustrative fallback placement is reserved for older stations without a schedule.

Reading the earthwork, bridges and water

Cutting benches and berms follow the section geometry. Cutting cess and bench U-drains are drawn only on terrain-trimmed treads that exist; they stop at missing benches and structural transitions. They are not automatically added to fill berms or the embankment toe. Section drainage dimensions override the defaults, and narrow channels can reduce the depicted size. Inspect the section and drainage design before treating any visible channel as an engineered drainage solution.

Return walls are seated against approach slopes, tunnel portal cover joins the hillside, and bridges use the shared resolved family and floor geometry, with the scheduled openings and pier positions. Square support lines retain the actual obstacle direction. Road traffic follows the road grade. Rivers use a water surface over a recessed channel; an aqueduct's water is within its supported trough. Water levels without recorded evidence remain illustrative.

The original cab ride

Cab ride puts the eye on the track, two and a half metres above rail, and runs it along the alignment. It is a picture of the design, not of the ground: the formation and batters the earthwork model assumes, the structures the profile implies, the platforms the station plan placed, and the crossings the schedule resolved, draped on terrain sampled at thirty metres. This original renderer does not add the trees, buildings or detailed station scenery of Cab ride 2. Its engineering objects follow the design modules.

1 2 3 4 5 6 7 8 9 10

1. 1 The readout: chainage, direction, radius, cant, grade, the works being built, the permitted speed and what governs it, the scheme's cut and fill, and what is coming next.
2. 2 Callouts for the deepest cut and the highest fill in shot, each with its chainage.
3. 3 The cut/fill key — three bands a side, in the same red and blue the long-section uses.
4. 4 The long-section strip: the whole line with cut and fill shaded, the structures banded, the stations ticked, and a marker that moves with the ride.
5. 5 Transport: run/stop, speed multiplier ×1 to ×8, and the direction of travel.
6. 6 The three cameras, and the chainage slider.
7. 7 Layers — cut/fill, terrain, earthwork, furniture, track, long-section and the panel, each independently off, folded behind one button that carries the count of what is off.
8. 8 Scene (the ground, the detail, the lens, the light, and a variant beside this one), Reset view, the sound with its level and the horn, Full screen, and Save.
9. 9 Which way is north.
10. 10 A plan inset showing where on the line the eye is, and which way it is looking.

Keys: space run/stop · 1 2 3 cab, chase and orbit · ← → nudge 25 m (Shift 250 m) · , . previous and next feature · Home End · R reverse · L reset the view · F full screen · S save the frame · Esc close the open panel, then the window.

Where a DEM has been kept, the terrain mesh stops at the top of the batter rather than running across the corridor, and the batter is drawn out to where its design slope actually meets that surface. This is a drawing, not a quantity: the structures engine still prices earthwork against level ground across the section, and the difference between the two is the error that assumption carries.

The ground under the picture

The terrain fan takes its colour from whichever basemap is chosen in the ground selector — the same rasters the plan view draws. A corridor that runs through orchard, dry scrub and a village reads as one green wedge under slope shading and as three obviously different things under satellite, and the difference is the difference between land that costs money to take and land that does not.

Setting-out marks

TS, SC, CS and ST on the plan curves; BVC, EVC and the summit or low point on the vertical ones — a peg either side of the formation with a bar across it, at the chainages the solvers produced. They are already on the curve schedule and in the setting-out table. They are here because the question a ride answers that a table cannot is what a transition looks like, and that is unanswerable if you cannot see where it starts. A curve with no spiral in it is marked TC and CT, not TS and ST, because calling it otherwise would be a lie about a geometry that has no transition.

The light, and what it is for

The ground is lit from a fixed bearing chosen so the light comes across the line: an aspect that shades every north-facing slope the same as every south-facing one shows no landform at all. That is the right choice for a picture and the wrong one for a question, and there is a question. A cutting whose face is turned away from the winter sun stays wet; the identical cutting fifty metres on, whose face happens to point the other way, does not. Give the sun control a date and an hour and the light goes where it actually was — NOAA's solar position at this corridor's own latitude, on the clock its own longitude keeps — and the panel gains the bearing, the elevation and the day's length. Below the horizon the ground goes to ambient, because lighting a hillside from a sun that has set is the kind of thing that makes a drawing quietly untrue.

Two alignments, one camera

Where the project has variants, beside opens one in a second frame. The two share the chainage, the direction, the camera and every layer switch, so that anything different on the screen is a difference in the railway. Letting them drift apart is what makes a side-by-side of two pictures worthless — the eye cannot tell a changed alignment from a changed camera, and it believes whichever it saw first. The comparison panel already puts two options side by side as numbers, and numbers are how a decision is justified rather than how it is made: somebody looking at a variant that saves eleven crore wants to see what eleven crore bought.

A set of frames

Frames shoots every structure, every station and every finding from the same angle at ultra detail — off-screen at 1600 × 900, so a picture going into a document at that width was drawn at that width and not enlarged from nine hundred — into one ZIP with a CSV manifest naming the chainage and subject of each. A folder of thirty PNGs with no index is thirty pictures nobody can caption. The ride is put back exactly as it was found when the capture ends.

Project sheets

1 2 3 4 5 6 7

1. 1 Which sheet: the corridor is partitioned into 5 km packages — twelve of them here.
2. 2 Export this sheet, or all twelve, as DXF.
3. 3 The plan strip: track, land boundaries tagged at 25 m, boxed kilometre posts, curve data apex boxes and bridges.
4. 4 The profile band at 1:5000 horizontal and 1:500 vertical, on an independent 10 m datum per sheet.
5. 5 The seven-row L-section data grid — formation, ground, cut/fill, alignment, gradients — with exact chainage vertical callouts.
6. 6 Curve and track constant tables, and the legend.
7. 7 The title block: project title, division, sheet number and km range.

Basemaps

Each tile is drawn through an affine transform built from the plan coordinates of its own three corners, rather than the whole image being stretched to fit, so registration against the alignment holds to a small fraction of a pixel at any zoom. Each source is credited in the corner of the view.

Review and finish a PDF in PDF Studio

On the main and corporate websites, a PDF export first opens a preview. Check the page, use Search PDF or Text to inspect its existing text, and add highlights, text, comments or freehand marks. Choose Download to save an annotated copy, or Edit PDF to carry the document and your annotations into a dedicated editor page.

1 2 3 4 5

1. 1 Annotation tools: text, highlights, comments, drawings, shapes and images.
2. 2 Page operations, including merge, rotate, remove, extract and split.
3. 3 Page navigation and zoom; search is on the right of the same row.
4. 4 Download the edited document. Undo and redo sit beside the download control.
5. 5 Page order, with controls to move each page earlier or later.

Open Export → PDF Tools to start with your own PDF or images. Pages combines files and inserts, removes, extracts, reorders or rotates pages; split ranges produce separate files. Markup edits the objects you add. Layout crops page edges and adds page numbers or text/image watermarks. Use Download PDF when the result is ready. Original PDF text and drawing geometry are preserved; they are not converted into editable Word paragraphs or CAD entities.

Convert exports PDF pages as JPG images, adds JPG/PNG pages, and extracts existing text to basic HTML or Markdown. Camera/document photos can become PDF pages. Image-only scans do not gain searchable text: OCR, Office conversion, compression, repair and PDF/A conversion are not included. These tools process documents on your device; they do not send the PDF to a conversion service.

The editor keeps a local draft for up to 24 hours in the same signed-in browser session, subject to available browser storage. Download important work before clearing storage or signing out. Existing Pro, company and project-allocation checks still apply to engineering exports and restored project documents. Editing a PDF does not update the alignment, estimate, design approval or original project file.

In company chat, PDF attachments open in the compact viewer with search, page controls and annotation tools. Download saves your annotated copy; it does not replace the shared attachment. The document page is rendered as needed so that opening a long file does not wait for every page to be drawn.

A project presentation for technical review

1 2 3

1. 1 Complete meeting particulars and state the decision required from the review.
2. 2 The export describes the stage currently running and disables duplicate downloads.
3. 3 The activity strip remains at the bottom left while figures are being prepared.

Save the adopted design, then open Export and choose the project presentation (.pptx) named Project presentation. Enter the employer, revision, meeting title, objective and decision sought, then choose Download project .pptx. This export requires Pro. It assembles the route, alignment and profile imagery, design basis, structures, quantities, costs and review findings from the current project. Check the named alternative and cost snapshot before presenting it. The alignment and profile use engineering coordinates; the editable line diagram follows station chainages. Include the current plan and profile views adds images of the present zoom, overlays and annotations; a saved CAD drawing can also be included. Add an approved geographic location plan when the meeting requires one.

Use the deck as a starting point for a PEC or other project review: explain the objective, compared options, evidence for the recommendation, remaining risks and decisions requested. Complete traffic evidence, economic/financial appraisal, funding, stakeholder approvals and other scheme-specific inputs that the alignment does not contain. No universal mandatory PEC slide template or sanction is implied by exporting a presentation.

The Estimate justification and evidence fields and Review BOQ / EPC allocation are shared with the estimate justification report and tender exports. Complete them once, choose Apply export settings, then Save project to retain the notes and allocation decisions in the project. The presentation uses that same estimate and package split, so its cost explanation can be reconciled with the Word report and Excel schedules. A download alone does not save changes to the project.

Open PEC meeting evidence and observation replies to describe the Existing scenario and Proposed scenario, traffic-study and financial/economic appraisal evidence, land and clearances, and consultation with other agencies. Use Add observation / reply for each committee comment, its response/action, evidence reference and stated closure status. These entries give the presentation a traceable review record; a typed closure status is not an independent verification of closure. Save them with the same shared export settings.

In PEC / DPR studies and slide sequence, choose Detailed DPR / PEC review or NPG / network planning review. Additional proposal particulars accepts reviewed total track length, completion cost in INR, FIRR/EIRR percentage points and the appraisal reference for the opening proposal table. Use Study table template and Add study table to include project particulars, alternative comparisons, station facilities, bridges and tunnels, GIS constraints, land, commodity traffic, capacity, cash flows, sensitivity, implementation or consultation records. The templates provide headings with no example client figures. Paste an Excel range including its header row, or CSV, then choose Preview study table. The preview shows eight rows; the presentation includes every row with repeated headers and continuation slides. Add the study source, interpretation and its order within the chapter.

Mark numeric columns and select an optional editable column or line chart. Choose the category column and the series with consistent units. Declare units under Column types when needed. Missing observations remain gaps; explicit zeros remain zero. A series with no numeric observations or incompatible units is retained as a table; the preview explains why its chart is omitted. RAD does not calculate or infer traffic forecasts, FIRR or EIRR. Study tables and their references are retained by Apply export settings and Save project. Empty studies do not create placeholder slides; outstanding evidence is grouped at the end.

Expand Maps, station plans, drawings and project photographs to add local PNG/JPEG figures in batches, up to 10 MB each and 80 MB in total. Include the approved location and network maps, alternative plans, station drawings, GADs, tunnel sections, traffic maps and site photographs relevant to the project. Assign each figure to a section, enter its title, drawing/source reference, caption and order within that section. Every figure gets a slide with its full aspect ratio preserved. Related study beside figure pairs a compact table with the map or drawing when it fits legibly; larger tables continue separately. Remove individual figures when needed. Images are embedded in that presentation download; select them again after reopening the dialog.

Choose a coordinated document layout

1 2 3

1. 1 Choose one of six document layouts before preparing the export.
2. 2 The preview explains the visual treatment. Its demonstration blocks are not project quantities.
3. 3 Download the actual project in the selected layout after completing the issue details.

The Document layout selector shows six visual templates with a live Document layout preview. Choose the layout before downloading; its colour palette, typography, cover and section treatment apply to the supported document. The project data, quantities, rates, scope gaps and review findings remain the same across layouts.

Project presentation, estimate justification and tender dialogs can retain the layout with their shared export settings: choose Apply export settings, then Save project. A project without saved settings starts with Railway corporate. The separate feasibility and DPR publication dialogs retain their own export controls. Templates are RAD presentation choices and do not imply a prescribed Railway Board submission format. Other CSV, interchange and drawing exports retain their own established formats.

Explain the estimate to the client

Choose Output → Export deliverables → Estimate justification report to prepare an editable narrative in Word. This Pro export explains why the work and estimate provisions are needed, alongside the current applied route, quantities, head-wise costs and their source evidence. It complements the detailed estimate and tender schedules.

1. Enter the employer and revision. Expand Estimate justification and evidence and supply the Estimate / sanction reference, Price level / rate date, purpose, authority/survey background, estimate coverage, construction period and basis, necessity, scope, quantity basis, rate sources, land provision, other charges, exclusions and the recommendation or decision required.
2. If revising an earlier estimate, enter its amount in INR, date and reference, with the reasons for change. A blank previous estimate is unknown; do not enter zero to stand for missing evidence.
3. Expand Head-wise estimate justification to explain the physical provisions, quantity and rate changes, and drawing/source references for each estimate head.
4. Open Review BOQ / EPC allocation and choose Load allocation review. Review the suggested package for each estimate item and record contract-specific exceptions.
5. Choose Apply export settings, then Save project if these particulars should be available next time. Applying settings changes the project and is subject to its normal editing controls. Downloaded Word or Excel edits do not write back into the project.
6. Choose Download justification .docx. Check the explanation, rate and measurement evidence, cost reconciliation and outstanding items before submitting it to the client. The same download is also available in Tender schedules & EPC draft.

Missing quantities, rates or explanatory evidence remain identified in the report. Generated indicative rates are distinguished from saved detailed estimate rate sources. Entering a preparer, checker or approval authority name records a name only; it does not certify an estimate, record a sanction or establish that review has taken place.

Schedule G / G1 and the EPC preparation draft

1 2 3

1. 1 Identify the employer and revision for the draft; demonstration data is clearly named.
2. 2 Enter the actual tender reference and approved completion period. Blank fields remain to be completed.
3. 3 Apply shared settings or download Excel schedules, the justification narrative and EPC draft.

1. Choose Export → Tender schedules & EPC draft. Enter Prepared for / employer, Revision, Tender reference and the Approved completion period. These deliverables require Pro.
2. Expand Review BOQ / EPC allocation and choose Load allocation review. Confirm the suggested scope and record any whole-item overrides before downloading.
3. Choose Download schedules .xlsx. It separates Civil, Electrical/OHE and Signalling & Telecommunications, retaining the source quantity and rate basis, EPC scope, separate BOQ and items still requiring allocation review.
4. Review Schedule G stage/payment allocations against the adopted component prices. Enter the approved stage weights; do not assume a default percentage is a contract rule.
5. Review Schedule G1 itemised BOQ work separately. Reconcile inclusions and avoid counting the same scope in both the EPC price and a separate itemised payment.
6. Choose Download EPC draft .docx and complete employer details, dates, eligibility, securities, terms, approvals and annexures using the applicable issued tender.

Review the EPC and separate BOQ boundary

1 2 3

1. 1 EPC, BOQ and unresolved totals show priced amounts and unpriced item counts separately.
2. 2 Review each suggested allocation; use an override and note for a contract-specific exception.
3. 3 Apply the settings, then save the project to retain the decision across exports.

This starting convention follows the user's recent project packaging; the issued contract can require a different allocation. An override moves the whole estimate item and does not split or reprice it. Prepare separate measured component items when one aggregate contains both BOQ and EPC work. Unresolved allocation and unpriced work remain visible; neither is silently added to both packages. Valid zero values and signed credits retain their meaning.

A changed work description, component or unit invalidates an earlier inferred classification or fingerprinted override and returns that item to review. Recheck the scope and choose its allocation, or use Confirm for current item for a previously saved choice. Quantity and rate changes preserve the allocation; their current values are used at export time.

Use Apply export settings and Save project to retain the reviewed allocation. The Word justification, EPC draft and project presentation use the same scope result. Recheck the allocation when the source estimate changes. Schedule G's adopted contract price and milestone weights still need explicit employer-approved inputs; the estimate split alone does not approve a contract price or payment percentage.

CAD drafting in project coordinates

1 2 3 4

1. 1 Open Templates or import DXF / DWG; the toolbar also provides drawing and history commands.
2. 2 The inserted component has dedicated geometry and annotation layers; visibility and locks remain editable.
3. 3 A dimension records the length in project metres. This platform is demonstration geometry.
4. 4 Exact coordinates, grid/object snaps and Ortho control placement. Save project retains the drawing.

Choose Alignment → CAD drafting to prepare railway layout details and annotations in project metres. Use the alignment as a reference, organise geometry on layers, and draw lines, polylines, rectangles, circles, arcs, text and dimensions. Snaps and numeric properties help place and check details. Enter exact coordinates as E,N or relative coordinates as @dE,dN; F8 toggles Ortho. Use endpoint, midpoint, centre, quadrant or grid snaps as appropriate. Save the project to retain the CAD drawing in its .rads file.

Use the CAD workspace to develop station or platform outlines, access arrangements and review markup. Imported geometry must use compatible units and coordinates. Export DXF or DWG for CAD exchange, and SVG for a vector drawing; these exports require Pro. Import DXF / DWG preserves supported planar geometry, including ellipses, splines and hatch loops. Block inserts and arrays expand into editable geometry; multiline text and dimension graphics are flattened. The import report identifies expanded content, approximations, conversion warnings and skipped entities. Check that report and the source drawing before adopting the result.

DWG conversion runs locally through the packaged WebAssembly adapter. Conversion is not a promise of complete AutoCAD fidelity: 3D solids, meshes, external references and proxy objects remain outside the supported editing model. Native block/dimension associations, font placement, layouts and advanced multiline-text formatting require review. Drawing or moving a CAD line does not itself change the computed alignment, bridge design or engineering quantities.

1 2 3

1. 1 Imported blocks and arrays become editable entities. This example expanded three INSERT references.
2. 2 Sheared and mirrored text need comparison with the source. An approximation is reported separately from a skipped entity.
3. 3 Review the codec warnings and local DWG conversion notes even when no entities were skipped.

Insert a reusable railway component

1 2 3 4

1. 1 Search or choose a category, then select the component variant.
2. 2 Edit the model dimensions and labels; the preview regenerates from these values.
3. 3 Set project coordinates and rotation. Drawing extents include the rotated annotations.
4. 4 Insert the component as editable geometry in one Undo step.

1. In CAD drafting, choose Templates. Search the library or filter a category.
2. Choose a variant, then edit its labelled dimensions. Geometry uses project metres; track gauge fields explicitly use millimetres, and title-block scale uses a 1:N denominator.
3. Inspect the generated preview and its drawing extents, including annotations. Enter the insertion Easting, Northing and counterclockwise Rotation.
4. Choose Insert editable template. The component is added on dedicated layers as editable CAD entities in one Undo step. Save the project to retain it.

The library contains schematic starting points for layout coordination and drafting. A turnout symbol does not generate a switch design; a clearance-study outline does not encode an adopted SOD; a bridge or retaining-wall section does not establish structural capacity. Template-specific review notes identify the intended scope. Edit the drawing to match the adopted design.

44 editable components across 8 categories, generated from the actual library catalogue.

Title blocks are model-space frames converted from paper millimetres at the entered scale; they do not create a paper-space viewport or set printer scaling. Scale bars have actual model-space lengths. Chainage labels and drawing annotations are editable text rather than live links to the alignment model.

The packaged deliverables

When a detailed estimate is active, the feasibility/DPR cost summaries use its named components, head totals, charges and GST, with missing/unpriced items and provisional status carried into the report. They do not infer a bridge sub-breakdown from a custom component name. Confirm the active bill and its date before publishing a report.

The schedules

Interchange

The narrative report

Separately from the schedules, report.js writes the document that goes in the envelope, with every figure read from the model at the moment of writing so the prose cannot drift from the schedules annexed to it. It refuses to write what the model does not know, and lists those gaps rather than leaving them to be noticed. Its best page is the register of assumptions, gathered from every module — the page a hand-written DPR always omits, because whoever writes it does not have them all in front of them.

Accounts

Signing out empties the workspace and puts the gate back: the alignment, the cloud id, the save target, the undo history and the autosave draft all go — that last one especially, because a draft left behind would have been offered back by name to whoever opened the application next.

Requesting Pro access

Open Explore Pro from your account or profile to submit an access request. You can add a short message, see the request status and cancel a pending request. An administrator reviews it; submitting a request does not activate Pro. After approval, use Refresh access to read the current plan and expiry. Decision notes from the administrator are shown with the request. This workflow does not take payment or send an email.

Authorised administrators use /pro-admin with a separate sign-in. Approvals default to 365 days, with 30 days, 90 days and no expiry also available. The database controls who may approve or revoke access. See the approval setup guide for the required migration and administrator configuration.

The project hub

The header account menu’s Project hub opens My projects and Shared with me. Both are the same list from the database — row level security answers with your own projects and with anybody else's that has been handed to you, and the only thing telling them apart is who owns it. Each row carries what the project is (length, standard, where on the earth, the revision, when it was last touched) and who else is in it — shared with 2 people, or from Asha Rao · can edit. A box filters by name, because a hub that is useful is a hub with too many projects in it to read.

Sharing

Pro is required to share a project or create a read-only review link. The project owner and each participating editor need active Pro access for shared-editor writes and live team editing. Owners can still edit and save their own projects on Free. Read-only viewing stays free. Existing review links stay available until their normal expiry or revocation. Cloud comments, replies and review updates also require Pro for the owner and participant; reading existing comments and local notes stays free. Removing access, revoking a link and leaving a project stay available after Pro expires.

Only the owner can delete a project, change who has it, or share it onward. Being handed a project is not being handed the right to destroy it, and the database policies say so: an editor may write the document but never take it. An address with no account yet is not a refusal — it is held as an invitation and becomes a real share the moment somebody registers with that address. Nothing has to be accepted at the other end.

Your profile

Every figure on it is read off the rows the hub already fetched, and none of them are flattering by construction: a project that has never been solved is counted as unmeasured rather than as zero kilometres. A field nobody filled in is left out of the page rather than filled with a placeholder that reads like somebody's own words.

Deleting the account outright is the one thing the page says it cannot do. The key the browser holds identifies the project and grants nothing beyond what row level security already allows, and removing an account is an administrator's operation on the auth schema — so the page says so, and says what it can do instead, rather than offering a button that fails.

Review, and what changed

Comments are anchored to a place in the design — a chainage, a fraction along, and the revision they were written against — so when the design moves and the two readings stop agreeing, the comment is flagged rather than silently re-pointed. What changed compares two saved states at three altitudes at once: what a person changed, what it did to the line, and what it did to the quantities and the cost, with a rule that has been turned off first in the list.

The command palette

Geometry closes — 12 codes

Horizontal — 11 codes

Cant and comfort — 4 codes

Transitions — 5 codes

Vertical — 6 codes

Gradients — 6 codes

Coordination — 1 codes

Terrain and works — 13 codes

Crossings — 14 codes

Stations & Yards — 8 codes

Land and consents — 9 codes

Engine — 2 codes

Generated from the shipped standard presets. Project overrides are not included.

The presets, side by side

Minimum straight and circular-arc lengths also depend on speed; review the computed findings for the project design speed.

What the design speed does

The minimum radius for a speed is not a table lookup: it is derived from the cant relation and the two ceilings above it. At speed V, the equilibrium cant for a radius must be reachable within the maximum applied cant plus the maximum deficiency —

R_min = G · V² / [ 127 · (C_max + Cd_max) ]

— and the answer is checked again for the slowest traffic, because the same curve has to be ridden by a goods train at 60 km/h without exceeding cant excess. Where no single cant satisfies both, the engine says so in exactly those terms and offers the radius that would (R_MIXED).

The project file

Saved to this computer, a project is one Name.rads file: the JSON object below, including the available terrain grid and the OpenStreetMap extract used for its crossings. The project hub also keeps the OpenStreetMap extract; terrain tiles are downloaded again when a cloud project is opened. Imported survey surfaces and the design's ground levels are retained in both kinds of save.

Older .rads/.radsupport pairs still open together. If the support file is missing, the app can download the missing data again. The next save includes the available data in one .rads, without a separate support file. Older .json projects also open and are saved as .rads the next time. Output → Export deliverables → Project file (.rads) writes the same complete .rads for sending to somebody as a single attachment.

One JSON object, round-trippable; this abbreviated example shows the main design inputs:

{
  "format": "railway-alignment",   "version": 1,
  "name": "Rolling plateau — Beed to Kalamb",   "division": "",
  "created": "…", "saved": "…",
  "standard": "IR-BG",
  "design":   { "V": 110, "Vslow": 60, "startStation": 0 },
  "limits":   { "gauge": 1676, "G": 1750, "cantMax": 165, … },
  "considerations": { "structures":…, "crossings":…, "stations":…,
                      "recon":…, "avoidance":…, "takeoff":…, "multitrack":… },
  "routeDesign":    { "from":…, "to":…, "via":[…], "demRes": 60, "V": 110 },
  "ips":    [ { "E": 487384.997, "N": 2099077.668, "name": "IP1",
                "R": 1075, "cant": 95, "Ls1": 90, "Ls2": 90,
                "autoCant": true, "autoLs": true }, … ],
  "vips":   [ { "station": 5050, "z": 553.128, "name": "V1", "L": 50 }, … ],
  "ground": [ { "station": 0, "z": 512.62 }, … ],
  "geo":    { "lon0": 75.88985, "lat0": 18.78225,
              "E0": 500000, "N0": 2077565.203,
              "from": {"lat":…, "lon":…, "name":"Beed"},
              "to":   {"lat":…, "lon":…, "name":"Kalamb"},
              "zoom": 11, "demRes": 60 },
  "crossings": { "overrides": { … } },
  "stations":  [ … ],
  "bridges": { "bridge-id": { … } },
  "estimate": { "planHead": 11, "detailed": { … } },
  "terrainSurface": { … }, "surveySurface": { … },
  "survey": { … }, "support": { "terrain": true, "osm": true },
  "compliance": { "strict": false, "overrides": { … } },
  "land": …, "existingYards": …, "multitrack": …,
  "overlay": { "layers": […], "shapes": […], "nextId": 1 }
}

The CSV columns

Setting-out table

Chainage · Station (m) · Easting · Northing · Rail level · Radius (m) · Hand · Cant (mm) · Bearing · Grade (%) · Ground level · Cut(−)/Fill(+) · Notes

The ground columns appear only when the project has a ground profile. Tangent points, summits and low points are always present as rows whatever the interval, and the Notes column is what says which is which.

Horizontal curve schedule

Curve · IP Easting · IP Northing · Deflection · Hand · Radius (m) · Degree (30.5 m) · Ls entry (m) · Ls exit (m) · Tangent T1 (m) · Tangent T2 (m) · Shift p (m) · Arc length (m) · Total curve (m) · External (m) · TS · SC · CS · ST · Cant (mm) · Eq cant (mm) · Cant def (mm) · Cant excess (mm) · Lat accel (m/s²) · Ls required (m) · Governed by · Vmax (km/h)

TS · SC · CS · ST are the four tangent-point chainages — tangent-to-spiral, spiral-to-curve, curve-to-spiral, spiral-to-tangent — the same four points the DXF marks T1/J1/J2/T2 in Figure 9.1. Governed by names which of the three transition criteria set the length.

Vertical curve schedule

Curve · VIP chainage · VIP level · Grade in (%) · Grade out (%) · Change (%) · Type · Length (m) · Radius Rv (m) · BVC · BVC level · EVC · EVC level · Mid-ordinate (m) · Turning point · Turning level

Compliance report

Level · Reported as · Category · Code · Rule · Location · Chainage · Description · Value · Limit · Unit · Reference · Options

Level is the rule's natural severity and Reported as is what it was reported as after strictness and overrides — so a re-graded finding shows both. The footer names the strictness mode and every overruled rule.

Cut and fill report

Chainage · Difference · GL · FL · Level diff · Track centre · Curve · Formation top width

Signalling and interlocking schedule

Station · Chainage · Item · No. · Type · Reads / Connects · Turnout · Operation · Locking · Aspects · Remarks

LandXML 1.2

Reads into Autodesk Civil 3D, Bentley OpenRail and 12d Model.

DXF (R12 / AC1009)

R12 is deliberate: it is the dialect nothing refuses. Everything is in real-world metres on named layers, so a receiving office can freeze what it does not want.

Ground and survey imports

How a route becomes a drawing

Notable implementation choices

The test suite

Automated checks cover geometry, compliance rules, terrain, persistence, estimates and exports. The repository also has interface tests, TypeScript checks and a production build check. The geometry is verified three ways:

1. Against closed-form results derivable by hand.
2. Against an independent numerical method — Simpson quadrature for the Fresnel integrals, finite differences for curvature and grade.
3. By invariants that must hold for any valid chain: position, azimuth and chainage continuous at every element joint, curvature from dθ/ds matching 1/R, sampled spiral arc length equalling Ls, and the projection round-tripping chainage and offset.

The compliance engine is verified on its own terms: that every rule carries a title, a real category and a rationale; that issue ids are stable across a re-solve; that strict mode and per-rule overrides resolve as documented and survive a save and reload; that each new rule fires on a case built to trip it and stays silent otherwise; that terrain rules stay quiet without ground data; and that a rule made to throw reports itself as RULE_ERROR without taking the rest of the report with it.

Multiple tracking is verified end to end rather than in pieces: a corridor with a known railway in it — twelve kilometres straight, a 700 m radius curve through 60°, sixteen kilometres straight — is analysed, planned and then actually designed through the router, and the finished centre line is measured against the existing one. It comes back one track spacing off it, to within 50 mm, over four hundred samples; the 700 m existing curve reappears as a 705 m curve on the new line, which is the radius offset to the outside; and the same corridor at 160 km/h leaves the formation for the curve, comes back, and is shorter for it. Both designs finish with no compliance errors.

test.html provides browser geometry checks; the full repository suites also exercise project saving/reopening, bridge geometry, estimate measurements and paise rounding, workbook formulas and application integration. A passing software test does not validate a project’s field data or rate applicability.

Checking the database policies

supabase/check/run.sh applies every migration to a throwaway local Postgres and then asks the policies what they actually allow: that Bob can read the project he was given and not write it, that an editor can write it and not take it, that Carol can see none of it, that an invitation survives until the account exists. It needs a local Postgres and an account that can create roles, and it never touches the real project.

How this manual is kept true

The screenshots are captures of the running application. Earlier corridor figures use the Beed–Kalamb worked example; this edition adds current task navigation, saving, detailed estimates and bridge workspace figures using explicitly illustrative project data. Older retained figures may show earlier toolbar layouts. Follow the command paths in the text.

The newer captures are reproducible with tools/shoot-workspaces.js. The earlier docs/manual/shoot.js covers the original route walkthrough and needs adaptation to current navigation and sign-in before a full recapture. Neither script turns demonstration quantities into an approved engineering design.

The compliance catalogue in Chapter 19 and the standards table in Chapter 20 come from the engine's rule and standard definitions. npm run manual:sync regenerates their values; npm run manual:check detects stale tables and missing links or images. The weekly documentation workflow runs Mondays at 03:17 UTC and opens a review pull request only when generated content changes. It also rebuilds the training page and PowerPoint from their reviewed course source. It does not invent instructions, refresh screenshots, update the editorial date or claim a review happened. The workflow must reach the default branch and Actions must be permitted to create pull requests. Check links, captions and printed pagination after editing this book.

The three server routes

Every reply is read through js/core/api.js, which turns a gateway page, a stopped function or a missing /api into a sentence saying what happened and what to try next — rather than the JSON parser's complaint, which names no status and suggests nothing.

Keys, and where they go

Without the two environment variables /api/features still answers; it just says overpass (uncached) and pays the full round trip every time.

Hosting

vercel.json carries the whole of the hosting contract: a 60-second maxDuration for the functions, clean URLs, a cache policy per path, and a strict content security policy that names every host the page may reach — the Supabase project, the tile servers, the terrain bucket and Nominatim, and nothing else. The service worker is served no-store so a deploy is picked up.

Links in email

A confirmation or sign-in link is opened from a mail client, and often on a different device from the one that signed up. http://localhost:8731 on a phone means that phone's own machine, which is running nothing — so the link cannot be the address bar of whoever asked for it. Config.siteUrl states the public address once and every auth email uses it, whichever host the request came from. Blank it and links fall back to the current origin, which is what a purely local install wants.

The database

Apply the migrations in supabase/migrations in order. Every one is idempotent and safe to re-run — from the SQL editor in the dashboard, or with supabase db push.

Seeding the worked examples

After 0003, paste supabase/seed_samples.sql into the SQL editor. For a script, or a rebuild that should not involve a browser:

SUPABASE_URL=https://xxx.supabase.co \
SUPABASE_SERVICE_ROLE_KEY=eyJ... \
node tools/seed-samples.js

That path needs the service role, because the table has row level security on and no write policy, so a browser key is refused by design. node tools/seed-samples.js --sql regenerates the SQL after changing an example. Either way it upserts on the slug, so running it again corrects rather than duplicates. tools/seed-samples.js is JavaScript and will not run in the SQL editor; the file to paste there is supabase/seed_samples.sql.

The access model, in one page

The data

The engineering

• The router knows the ground, and what it has been told. Geology, ownership and utilities can be given to it — as reaches, as a cadastral layer, and from the corridor query — and a cost surface can be painted by hand where judgement is the only source. What it still has no idea about is groundwater, and where the stations need to be.
• Multiple tracking cannot know whether the line is needed. That is a traffic question, and the traffic is not in the map. Nor is which side of the existing formation the land is available on.
• Steep country defeats it. Where a railway would need spirals, switchbacks or long tunnels to gain height, it says so rather than pretending — but it will not design those for you.
• One running line is designed at a time. A doubling is still one centre line.
• Simple curves, clothoid transitions, parabolic vertical curves only. See Chapter 9.
• Earthwork is a trapezoid unless sections are cut. Given a terrain grid, real cross-sections are cut with benching, berms and side-hill geometry, and volumes taken by Simpson's rule. Without one it falls back to a trapezoid on a single formation width — and says so, reach by reach, rather than letting the two be confused.
• One projection, one scale. A transverse Mercator grid on the corridor's own central meridian, scale factor 1. Scale error is reported, not corrected; there is no geoid model, so levels are what the terrain tiles say relative to their datum.
• The standards presets are starting points, not certified values.
• The perspective views combine engineering geometry and illustrative scenery. Cab ride 2 station details and terrain shaping do not alter measured quantities or establish design adequacy.
• The bridge workspace produces preliminary general arrangements. Wing/return wall profiles, footings and drawing references do not constitute structural, geotechnical or hydraulic approval; the outstanding detailed checks must be completed separately.
• A variant is a set of differences, not a fork. Two variants overlapping the same chainage cannot both be active, and a variant whose tie points are edited away no longer applies. Both are reported rather than resolved.
• An imported survey does not extend past where it was taken.
• The assistant is only as good as the engines it calls, and it costs money. Its prose is not a checked document.

Land, and money

The land boundary is a preliminary width drawn from the geometry the designer has fixed — the toe of the earthwork, plus a margin, rounded up and banded into lengths of at least 100 m because a boundary that steps in and out every twenty metres is a toe line with a margin added, and nobody pegs that. It is not a schedule of acquisition: that needs the revenue survey, the plot numbers, and everything the ground tells you that a terrain model does not.

What the engineer is signing

Everything in this software is a proposal supported by stated arithmetic over stated data. The compliance report says which clauses were tested and against what limits; the provenance panel says what the ground is known from and to what accuracy; the estimate says which of its rates have a schedule item behind them; the register of assumptions in the report gathers the rest. None of that transfers responsibility. A design leaves this tool as a first pass that a competent engineer has to verify against the governing code, the approved schedule of dimensions, the revenue records and the ground itself.

IRUSSOR 2021 — formation, bridges, permanent way

Indian Railways Unified Standard Schedule of Rates 2021, Railway Board, Ministry of Railways. Issued 28 July 2022, effective 2 December 2022, superseding IRUSSOR-2019. Price level 2021. It covers the three chapters the civil side of a new line is built out of: formation works, bridge works and permanent way works.

DSR 2023 — buildings, platform finishes, site works

CPWD Delhi Schedule of Rates 2023, Volumes I and II, civil works — the schedule the station buildings, platform finishes and site works are priced from.

Catalogue sources and their limits

The catalogue preserves 4,249 extracted variants, including source ambiguities instead of silently inventing units. Examples needing original-source review include DSR 5.13's unclear unit, unnamed thousand-unit carriage rows, and CR 172058's kilometre versus tonne-kilometre basis. Check correction slips, taxes and included work separately. Availability of a link or matching code does not certify the adopted rate.

In Basis & charges, record the railway zone, location, rate authority and adjustment basis. USSOR and DSR indices apply to their respective published rates: 100 leaves them unchanged, 110 adds 10%. An entered index is your project assumption, not an automatically fetched official local cost index. Project/quoted and analysed rates are adopted directly.

How to use them here

1. Open Detailed estimate from Output or the estimate panel.
2. Choose a component and search the rate library by schedule, chapter, item code or description.
3. Enter measurements, verify billing units, and record local adjustments for the project's railway zone and location. Use sourced custom items for gaps or specialist work.
4. Review unpriced items and provisional allowances, apply the bill, and save the project.

The catalogue preserves 4,249 extracted item variants. It is not a claim of complete coverage of every schedule and correction slip; source and unit warnings remain visible.

Load these with Explore worked examples from the opening question, or from the palette.

A longer case study — a real corridor between Nashik and Dahanu, with its own ground, curve and station data and the scripts that produced them — lives in study/nashik-dahanu/.

Railway Alignment Designer · The Manual · Edition 3 · Revised 15 October 2026
www.radrailway.com