While having algorithms and computers dictating every aspect of train movements, crew scheduling, resource allocation is efficient and in a sense optimal, I think there's something compelling to be said about having a system that can survive with human-rememberable patterns when such an optimizer fails. That it can fall back on (or have at the core) simple patterns that people can still operate without algorithmic in…
The train schedule as seen by passengers stays the same for years, often to the rail number in stations. What changes are the crews, wagons, locomotives, possibly routes on the railway (switches and reactions to delays and failures.) A friend of mine worked at an app used by a railway's personnel to know where to go next. The app was not particularly complicated but the backend, which has been running for ages, took a long time to run. I don't know the details.