Hi
There are a couple of driver commands by author "elstoko", "Set Selected Signal State" kuid2:368725:60002:10 and "Set Signal Ahead" kuid2:368725:60003:6.
The "Set Selected Signal State" command can be used to set any signal on the route while the "Set Signal Ahead" will set the first signal in front of the train. One thing with these commands, if you select the correct option they will light the calling on signal correctly on the old Auran UK signals to allow a loco to pass and couple to the rear of a train.
Regards
Brian