It would be very nice if you could maybe set it up in TSW5 so that you can play with realistic traffic because it is very boring when you know that all the traffic lights are always green and so you have to expect delays or train cancellations like in real life - these are things that I miss in all TSW parts.
Randomness is an oft repeated request. However it might have to come hand in hand with some sort of signaller/controller mode. The real railway employs a lot of people to manage services in the event of disruption, as you don’t want trains running late on their diagram the rest of the day (particularly with the “Trust” delay penalty payment scheme between Network Rail and the train operators). Even more important if you end up with train crews off diagram, the service would deteriorate into a complete shambles, though not so much an issue in the simulated world.