I actually have the same issue with busses right now. The game is acting real smart with assigning each line one side of the road. However my lines are linear, so one of the passes the busses require a loop to get to their assigned side…
For the trains I wish there would be a way to declare platforms ‘excess’. So that you can have fixed platforms for lines (that you can choose) but in the case of express lines or freight these can be freely picked by these lines.
Would keep the advantages of both. Additionally you can have rail that is used for through traffic, but in a jam can be used to handle the excess of trains at the station.