“I started to write this guide purely on basis of personal experiences, deduction and observation during my game play. If you see any error, have remarks or would have more information (examples, typical situations) please leave a note. thank you.”

The Train Fever signalling guide

1. Concepts
Signalling in Train Fever is simple, but one has to know a few concepts to understand why trains behave in a particular way.

• signals are the active, even deciding components to set up a path
• signals will split a path into blocks: areas where a train is safe
• only one train per block is allowed
• a train in service will follow it’s path dutifully, and will never deviate.
• a train will look ahead on it’s path to verify if the path is clear, nothing else.
• A train can not change a path (e.g. looking for an alternative way)
• when a train’s destination is lost, (e.g. path is broken or station is destroyed) the train will try to go to it’s next destination, and even turn around on it’s track if needed (very annoying if on double track). This happens even when the game was paused during the interruption of the path.

So, once we understand these basic principles, setting up an adequate signaling is quite easy. Important is to understand that signals decide how the line’s path will flow, and that they only control the trains which are dutifully following that path.
An essential tool in the decision where to place signals are the line screens. They will show the path(s) of the line(s) on top of the tracks. That way it is very clear how the trains associated with each line will run. Both the general lines screen, or the individual line screen are useful. Use those often.
2. The general guide lines

There are only four reasons to place a signal:

• to influence the flow of the line
• to secure a spot where two lines come together
• to add more capacity on a track
• to prioritize traffic (thanks Isidoro)

These are the only situations and considerations for which one needs to place signals. And remember that a train only looks to the next signal ahead on its active path to decide if the path is free, and will not deviate from that path.

2.a. To influence the flow of a line
The path of a line between two stations is done by simple path finding. The computer will look for the shortest route from A to B. Often that path will not be the most optimal choice. Most often we will want to split the path in opposing directions so trains are not running head to head on the same track. Using signals at a few strategic positions are here key. In a few cases we will need waypoints or uni-directional signals to get the path right.

 2.b. To secure a spot where two line come together
At points (UK) or switches (US) tracks join or split. For Train Fever you don’t have to secure splitting tracks, but you do have to secure converting tracks. Both tracks that are about to convert need to have their signal. They will protect the upcoming trains from colliding. The selection of which of both trains gets a clear signal is on basis of “first comes, first serves”.

 2.c. To add more capacity on a track
On longer stretches of single direction track, we would like to be able to run more trains one after the other. Therefore we are going to use signals to divide the track section into smaller blocks. Each block can hold one train. A train can only enter the next block when it is free. This way we are able to raise the capacity of a line. The closer the signals are place together, the more trains can enter a section of track simultaneously. Placing signals closer together then the length of one train has no real added value.

2.d. Prioritize traffic (thanks Isidoro)

One can prioritize fast traffic over slow traffic by constructing a bypass. The path of the slower traffic is send over de loop, the path of the fast traffic goes straight. By placing one or more signals in the bypass loop the slower traffic is hold up. The straight track for the fast traffic may not hold any signals.
To be continued? You decide!