You should read the description of the "Run Around Ex" command.
<kuid2:117667:83:3> Run Around Ex
Run-Around command that will first check the existence of any back-locomotive.
If one is present, driver is simply moved to that locomotive, otherwise, regular run-around is performed.
In all cases the driver is put in the new front-most locomotive, and train's logical forward is changed.
Another possible command is
<kuid2:70791:9001:1> Change Train Direction
This driver command changes only the driving direction of the train. No Runaround is accomplished. The driver changes automatically to the
frontmost locomotive if possible.
Peter