Factorio Forums

The train travels from station A to station B.
If there is a station on the way of the train, then the train does not pass this way, but always takes a detour. But if there is no other way, then the train travels through the station. Why can't the train pass through station C if this route is shorter?
It is necessary to do it - if station C is turned off, then it would not interfere with the passage of the train.

Not a Bug

https://wiki.factorio.com/Railway/Train_path_finding wrote:When the path includes a train stop that is not the destination -> Add a penalty of 2000.

For pathfinding, because of penalty of train stop not in path, longer path is "better"

I think the idea behind the panalty for train stops is the following:

If your train takes a path where it traverses a train station, but for whatever reason has to stop along the way at some red signal, your train could possibly block the entrance/exit of that train station. As a consequence, another train that tries to get to that train station cannot access it -- and everything because your first train decided it was more important to save some fuel by taking a slightly shorter route.

As has been said, this is working exactly as it should. Check out the wiki for pathfinding details.

If the station is turned off, the train will not go to it, therefore you can use this route for the train. Is not it logical?

Disabled station may become enabled and another train might stop in it for undetermined length of time; so stations on path have fixed penalty for pathfinding regardless of their current state.

You can put a station on the long path too to equalize the penalty if the behavior is annoying you.