Rapid Transit has never been touched to my knowledge and that’s one of the OG routes. They can’t even retrofit the 1442 with a better sound set!
He may mean the TOD4 system mate, that didn't come in till TSW 3, and is the current standard for all updated routes atm.
RT got a new timetable, one that was broken on release I might add, but I don't think they did much work on the route itself. Definitely got less work than what GWE got around the same time, which mind you aged poorly enough it needed to be remastered again anyways.
See below… What I thought and the 1442 remains one of the worst trains for audio in game(at least the UK Hitachi IET’s in game are prototypically quiet in the cab).