Two small issues regarding the reversing of vehicles.
1. Here's an excerpt from Experimental's default Simuconf.tab regarding reversing vehicles:
---
# These settings determine how long that it takes a train-type convoy to turn
# around when it reaches the end of the line. They do not apply to road vehicles
# or aircraft.
#
[...]
# All times are in milliseconds (1000 = 1 sec), assuming that the game is set to the
# normal speed (i.e., not fast-forwarded).
unit_reverse_time=1500
hauled_reverse_time=2500
turntable_reverse_time=4000
---
It occurs to me that these values are something of an anachronism in recent versions of Experimental, given that many values (e.g. loading times) are now given in in-game seconds/minutes rather than real-world milliseconds. Moreover, 1500 millliseconds represents a different amount of in-game time depending on the scale of the map in question. I am not sure how simple it would be to convert these values to in-game seconds/minutes.
2. While thinking about this, I was reminded of another oddity of reversing behaviour. Vehicles which are convoy spacing (e.g. at the end of a route) will not begin the reversal process until their scheduled departure time. So if a vehicle is scheduled to wait for 10 minutes until departure, it will not reverse until the end of this period. This seems strange, given that whatever processes are associated with reversing could presumably be undertaken whilst the vehicle is waiting to depart. I suppose the optimal solution to this would be to have loading time be "departure time minus current time minus loading time", rather than the current "departure time minus loading time" -- in order words, to subtract reversing time from loading time. I'm sure I recall some discussion of this being implemented in the past, but I cannot recall the outcome.
Edit: upon further examination, it appears that this *does* happen after all -- at least to some extent. I feel a little silly for not having noticed it all this time! So I retract point 2 for the time being.