cmul

Which is why ATO (automatic train operation) is most often found in subways where the platforms can be equipped with gates to keep passengers out until a train has stopped safely. Suicide by train and level crossings are a nightmare in risk management for railway safety, hence also (new) high speed tracks are usually planned without any intersections with roads or paths, at respective additional costs.

Imho, the major constraint for railways in most countries is policy, not technology. In the US and many large (surface area) countries, railways primarily serve for freight transportation and, to a shockingly underdeveloped degree, local commuters. In Europe legacy solutions and differences of national systems, planning guidelines and even power grid cause problems. Some nations' railways are extremely underfinanced and have been driven to the brink of collapse in the privatizations of the early 90s with more than 30 years of missed investments. The rollout of ETCS tries to remedy that and so do ERA/EUG/ERJU but the coffers of many nations are rather empty/respectively other interests weigh higher (subsidies for streets, automotive companies, aviation and other big buckets like farming).

For German speakers: https://www.estw-simulator.de/index.html https://www.estwsim.de/cms/index.php

These have been around for a while and quite closely mimic (slightly older) German signalling specifications for signaller interfaces.

My company builds such systems as test and demonstration systems for real railway projects with respective functional safety constraints. If you're interested to learn more about the signalling infrastructure in Europe or Germany, feel free to ask.