Rail Signal Lab

0:00 Pause on crash/deadlock

Signal lamps

Green. The block ahead is free.
Yellow. A train has reserved this signal and is about to pass it.
Red. The block ahead is occupied or reserved by another train.
Blue (chain only). Some exits of the next block are open and some are closed. A train only goes if its own exit is open.

Rules worth learning

A block is the track between signals. Only one train may be in a block. Turn on Blocks to see them colored.
Trains don't brake for trains. They only stop for red signals and stations. No signal between two trains means a crash.
Signals go on the right-hand side of the direction of travel. Signals on one side only make the track one-way.
Chain in, rail out. Chain signals at the entrance of and inside a junction, a rail signal at each exit.
The block after a junction must fit your longest train, or a waiting train blocks the junction with its back end.
Trains can't U-turn. They reverse only when departing a station, and only with a locomotive at each end.
A loop with N trains needs at least N+1 blocks.
Two-way track deadlocks when two trains meet head-on. Prefer one track per direction.

Controls

1–7Pick a tool Right-clickRemove what's under the cursor; drag to remove track SpaceRun or pause .Step one second BShow or hide block colors DelDelete the selected train, signal or station EscSelect tool

Scale

One grid square is one locomotive or wagon long, so train and block lengths are in car lengths. Track runs in 8 directions and turns in 45° curves, like in Factorio: a 90° turn is two curves and takes a 3 by 3 area. Add straight or diagonal track between the curves to make a bigger loop.

Drawing track

Drag from where the track should start to where it should go and the planner lays the curves. Start a drag on the end of a track to extend it, or on the middle of a track to branch off with a switch. Close a loop by dragging back onto its first piece.