The two Auran ones I use (
<kuid2:30501:22006:5> Portal Basic
<kuid:-25:1264> Portal)
can create, remove, or return trains. Trains returning have a choice.
They can return from the same portal or choose another portal.
They can also choose one of the following.
1) "Train is not loaded or unloaded."
2) "Train is loaded only."
3) "Train is unloaded only."
4) "Empty trains are loaded, other trains are unloaded."
I have started to place a blank baseboard some distance away from the route with 6 portals set up, one for each of the above, one for the exit of trains, and one for the returning trains. Other portals are placed to return the trains to the correct portals on the route.