Hello, James!
Recently I make some railway diagrams thanks to times_history window.
In Simutrans-Extended game, the train will depart at not the scheduled time, but the scheduled time + reversing time.
If you are using different type of vehicle on the same line (ex. local and express), the difference of reversing time is more sensitive and effective when traffic become heavier, there is no punctuality.
On the other hand, the vehicle can reverse until the scheduled time comes.
In particular, it should be changed the waiting time and reversing time like "reversing->waiting."