I'm no expert but UK steam practice at termini was to run the whole train in to the buffers (not literally!) Then a station pilot loco would haul the empty carriages off to carriage sidings (sometimes miles away) for servicing, which would release the mainline loco to go off to a separate loco depot.
For Departures a new set of carriages was brought in from the carriage sidings (having the observation car shunted and turned to be at the right end of the train) The station pilot loco would sit at the bufferstop until the main line loco backed on to the tain at the other end. On depature of the train the station pilot loco sometimes acted as a banker.
Many termini had serarate arrivals platforms and departure platforms and there was all this crazy shunting up and down of empty stock to and from the carriage sidings. Why have only two movements per arrival/departure when you can have eight?
