Nice; thanks for your hard work! I'm glad I can say I made a tiny contribution to the game.

Apologies. I have attached the save file and log file.

I have set the one of the supply trains to be in the bad state, south of the default spawn location.

A few more details regarding setting up this bug repro consistently:
For train B to get stuck: as train A is at the outpost to pick something ...

Trains seem to have a problem with leaving a reservation to go a different station when a reservation opens up.

In this situation, the "Building Outpost" was just reserved by the "Building Supply A" train and has reopened while the train is heading back; the train has reserved the "Building Supply ...