Did you instead want to build some central hub that grounds all train traffic if unreachable, or create a bunch of semaphores that anything can overwrite by accident or on purpose?

I'm genuinely curious here.

I can understand being intimidated by concepts outside your wheelhouse, but if you have a simpler solution you'd feel safe with i'm all ears.

I'm not saying this is all there is too it, but I am saying all the other design choices like recovery modes, operator experience, etc - should build around cryptography between tracks and trains.

We can call them cryptographic semaphores if that makes your brain turn on again.