Train fever: how the signals work and what to do

In Train Fever, the signals work in an usual way.

Here are simple rules to help build a network.

First rule: a line usually follows the shorter (faster path) It is a key feature that must be remembered when designing a network.

The Signals: when are they taken into account?
When they are located at the right side of the track when the train progresses on the track.

The signals: what do they do?

Signals do two things:

-they separate a track in segments to indicate the presence of a train in the next segment. When a train is present on the next segment, the following train stops, waiting for clearance.

-they ascribe a value of direction to the line (one way/two way line) Very important.

The design of a network is composed with these principles.

Example: two stations belong to a track ring. Making a line between the two stations is by default a two way line since going the ring measures more than the distance than one of its segments.

Example: one way line only exists within a ring/loop. If there are not two ways to join a station, then a one way signal is ignored. And the line remains by default a two way line.

Now the big part:
Ingoing and outgoing directions:

Ingoing: means that when facing, a train enters the line with a signal on the right side of the track.

Outgoing: the other direction.

One single train occupies a track at one time.
Consequence: a line is either ingoing or outgoing relatively to a train at a time.

This is a core principle.
By default, a line is first ingoing and then outgoing.

Effects of the signal:

Lines are computed to be the shortest and the fastest.
As a result, as soon a signal is placed along a track, it downgrades the speed of the line (signals introduce a potential loss of time as it is assumed several trains are going to travel the line and then trains are going to stop at a signal)

Effects on double track: when two points are connected by double tracks, placing a signal on the track travelled by the line pushes the line on the side track.

Consequences on passing overs: passing overs are used to enable trains coming from opposite directions to pass each other over.

Usually this is solved by using Y tracks or X tracks. But they do not exist in this game that relies on lines instead.

How to build a pass over and how it works:

Place and connect the sidings as usual.
Note which side the line follows.
180° rotation
place a signal on the right side of the siding track that the line does not follow
180° rotation
place a signal on the right side of the siding track that the line follows.

As a result, the line is split into two segments that are both only ingoing directions.

What happens is the following:

In a configuration with a double track running from South to North.
The line by default runs from South to North, then from North to South.
By placing a signal on the other siding track, the segment is made running from North to South first and then from South to North.
When placing a signal on the track that the line follows, this line is pushed on the other track. Which contains a signal that pushes it back to the first track in the siding.
Contradictory configuration: the line is supposed to be running at the same time from South to North first and North to South first.
As a result, each side of the line is assigned one value in direction only.

Stations with several platforms:

A three platform station is either a three platform station or a two platform plus one platform station.

When all the platforms are connected to each other through three tracks running one next to the other, it is a three platform station.
When the third station is kept independent, then it is the other case.

As seen, everytime a signal is placed on a track followed by a line, it pushes that line toward a track running next to it. A line might be split over three tracks.

And so on.