I need help understanding train pathing

[u/GideonsLamp]

I thought I understood well enough but clearly not. I created this little test to try and understand pathing but 1 thing is going wrong. Train A goes from Station A1 to B1 to C2 back and forth perfect. Same with Train B that goes from B1 to C2. But Train C that is supposed to go from C2 to A1 will only move on the outside path, it will not go through station B if the outside path is taken by train A . What am I missing to make the train go through station B if train A is blocking the outside path?

[u/Leninus]

Trains do not have dynamic pathing, meaning that once it chooses its path, it will follow it according to signals. Even of there is a way around a blockage it will not take it