Unfortunately my jam entry was missing this central feature from its design since I spent too long struggling with the track editor and getting the trains to actually follow them properly.

I have now added it and a bunch more improvements to a post jam version available here It also has a fancy town generation system to import and export goods rather than the nasty last minute hack in the original, and a bunch more GUI elements to show supply, demand and inventories.

I realise the signal colours I used are actually for the reverse side. Real semaphore train signals are directional. I quite like it like it is though as it makes the game more of a puzzle.

There is still much more to do to turn it into a decent game, but this is what I had hoped to submit to the jam.
Have fun making ridiculously complicated railway networks!