Yet the actual system reliability and safety doesn't seem great. Signal outages happen nearly every day in the UK, and delay tens of thousands of passengers. Safety failures in signalling systems kill on average a few people per year.
How about a modern system, built with JavaScript-de-jure, running over 4G and WiFi, consumer GPS, "Download train-control from the app store", running on tablets or the train drivers BYOD phone, etc. How would it work out for safety/reliability?
I suspect counterintuitively it would work out much better. Simple cheap portable devices means a bunch of spares can be around always. "Phone battery dead? No worries, there's a tablet I can control the train from too". No WiFi? It also works with 4G or Bluetooth. Server down? It has a Peer connection backup. Hackers broke in? The system has safety logic built in to every device, and uses a consensus system so a few rogue systems can't crash trains. Power supply broken? We have 24 hours of battery, longer if I turn the brightness down.