Service Extra 11 is supposed to split the special train. Unfortunately there is one step missing, the cabcar should be be reattached to the one of the train parts. It is not in this service but also not in other services. It is not a very big issue, but it should be a small fix.
The cabcar in the middle of the train was never uncoupled. The second trains loco was uncoupled and the wagons were simply coupled to the first trains cabcar. Then the second loco was coupled in front of the first one and the special train was ready. When you disassemble the train again, you just uncouple the extra wagons just behind the first cabcar and couple them to the loco you uncoupled earlier and drove to the other track. I don't see a missing step or did I miss something?