If DTG really wants to immerse the player in realism, one of the most things that can contribute to that are SPADS. Currently in tsw2 if you run a SPAD, the game just cuts off leaving the safety systems unused, e.g PZB, KVB, TPWS, Tripcock, TVM-430 and others. Running a spad in tsw2 would contribute to the realism aimed for the game, like the player recovering from a spad, resetting systems and all that. My main point Is that make use of some safety systems
To be fair on most real railways, a SPAD would require the driver to be relieved of duty. They might be allowed to continue to the next station or a location where following services can pass, but no further. What I do feel the game needs is a better SPAD over-ride for situations where signals are at red for no reason, saved game bug etc.
It would certainly be more fun to end the sessioan deraiingl when possibly crashing into another train, then to get the current boring message. It may not be realistic since a SPAD is the railroad equivalent to "Game Over", but it would be more fun
I think it is way more complex than just disabling being kicked out of the service when spading. You would need to think about what would happen next. There has to be a reason for the red signal: the next part of the route is blocked by another train. If you too enter that block, some procedures like reversing or just stuff that TSW AI drivers and the game in general are not capable of handling which would all have to be resolved if you don’t want to be standing there stuck on the track unsure what to do instead of accepting you’ve made a horrible mistake by passing a red signal and trying again