The way this works is text file is setup containing each services Consist path and timetable. Any service can be selected as the one you wish to drive all others become AI services. One can have services ahead of you as well as behind you. When a service terminates at a station it can be directed to become another service. The timetable file allows loco's to automaticly swap ends at a station (a path has to be specified). All services exits all the time unless when commands otherwise.
Note, the routes signalling MUST be able to handle all the traffic. For an example for a loco to swap ends automaticly the platform concerned has to have some kind of "Calling on" signal otherwise the loco cannot enter the track with the rest of the train.
It appears the first version of the timetable operation is quite complex, but already a number of users have reported some success.
A doc has been released as well as a spreadsheet of an example (quite complcated) timetable for the US Surfliner route.
This is being hailed (quite correctly I think) a a major advance!