Trains don't go in for their maintenance on time

[ysg]

This is kinda annoying. When I setup trains to go in for their maintenance, they literally don't do it. Why? Some wait a few years (2 - 5) and break dozens of times before I force them to go into the garage and then on their way. Why is this?

[Yexo]

There can be several reasons for this. Please upload your savegame so we can have a look at what is wrong.

[ysg]

After I get such an example, I will.

[Yexo]

1. They can't reach any depot.
2. They can reach a depot but have to get (far) out of their way to get to it.
3. You've set the maintenance number to % instead of days (or the other way around) and as such it happens on other times than you would expect.