Transport Fever 3 Signals Guide: Path Signals and Deadlocks

By Tobias Lindqvist · Updated October 1, 2026

What signals do

Signals split your rail network into sections so that more than one train can use it safely. The official manual notes that the look depends on era: semaphore signals until 1950, light signals afterwards. They behave the same way; a raised arm means go, a horizontal arm means stop.

Path signals, not block signals

The developers confirmed in their fifth dev blog that Transport Fever 3 uses path-based signalling, as earlier games in the series did. A signal turns green when the train approaching it can reserve its own route up to the next signal. Trains do not block each other on track they are not going to use.

The manual gives a clear example: two trains can enter a station at the same time across a crossover, because their paths do not overlap. Strict block signals would have let only one of them through.

How far a train reserves

A train’s reserved path ends at the first of these on its route:

The developers said this is a change from Transport Fever 2. Trains now reserve past ordinary stops, all the way to a stop where they can change direction or to the next signal. In practice, signals are needed wherever trains are meant to pass each other.

Important: stations do not count as signals, even if the station is a stop on the train’s line.

The classic deadlock and its fix

The manual walks through a single line with a passing siding in the middle and no signals:

1. Train A leaves its station and tries to reserve all the way to the far terminus, because there is no signal in between.
2. Train B does the same from the other end.
3. Each train’s path runs through the other, so neither can move. That is a deadlock.

The fix is to place signals at each end of the passing siding. Each train now only reserves as far as the siding, they meet there, and then each reserves the rest of its way once the other is clear.

How long should the siding be? The manual says to leave room for the full length of your longest train between a switch and the signal. One launch tips video suggests building sidings two to four times the longest train length, with signals at both ends.

A developer was also clear in the dev blog comments that the longer look-ahead does not make single track foolproof: if your signalling allows two trains to face each other, they can still deadlock.

Leave space after switches

Even with signals, placement matters. If a train waits at a signal placed too close behind a switch or crossing, its tail can sit across the junction and block a train on another line. In a compact layout, that blocked train might be the very one in the first train’s way. Move the signal back so a full-length train can stop clear of the junction.

One-way signals

Signals that face away from a train’s direction of travel are ignored. That means trains may keep to one track even when a second parallel track exists. To force direction, select the signal, open its detail window, and set the One-way dropdown to YES. A one-way signal cannot be passed from behind, so placing them on one side lets you set right-hand or left-hand running on double track.

More capacity on busy lines

• Double track with several signal blocks lets more trains run on the same route than a single track with sidings.
• Extra platforms at intermediate stations, with trains routed to different platforms at the ends, add more.
• Alternative terminals stop queues forming outside stations. If a train cannot reserve a path to its main platform, it can use another enabled platform. For trains the decision is made at the last signal before the station, shown with a blinking arrow in the line color while the line window is open. Every alternative must be reachable from that signal or you get a warning.

Line priority

By default every line has normal priority, and a train only reserves extra track when it would otherwise have to brake. The manual shows the downside: a slow regional train can slip in ahead of an express. Raise the express line’s priority with the buttons in the lower right of its line window. The dev blog explains that higher-priority trains reserve further ahead and get preference at signals, while lower-priority trains wait at red until they can continue.

There are no timetables to handle this instead. The developers said timetables were considered but left out, and priority is the built-in tool. See our lines and timetables guide.

Waypoints

You no longer need to build waypoint markers. In the line manager, hold SHIFT and click a valid spot to add a waypoint to the stop list. Trains must pass through it but do not stop. Uses include steering traffic, keeping noisy trains away from homes, and routing past a maintenance building.

Tram-trains

Trams marked Light Rail can move between rail track and tram lanes on streets. On rail they follow normal signalling and reservation; on the road lanes they follow street rules, so no signals are needed there.

Troubleshooting

• A red exclamation mark in the line manager marks a segment a train cannot reach. Problems can appear after you change tracks or signals, so check the warning icon at the top of the screen after rebuilding.
• Working on tunnels? Press G for underground mode, which a developer also pointed to for deleting track inside tunnels.

We have not found an automatic signal placement tool in any official source. For key bindings see our controls page, and for what else changed since the last game, read TF3 vs TF2. The full official page is in the game manual.