Trains are something that go from one station to another, whether scheduled or ad-hoc, and whether revenue or not. They are trains all the way from their departure platform, though any intermediate stations, to the arrival platform on its ultimate station.
Vehicles that move around inside a station's track area are shunting movements. They may be actual remarshalling operations, or it may e.g. be something that just before was a train when it arrived at a platform but now is heading for a holding track.
Trains and shunting movements obey different sets of signals. Main signals are only valid for trains. shunting signals are theoretically valid for trains but a Go aspect from a main signal practically guarantees that they will show Passing allowed.
The pieces of track on a station where trains regularly stop, depart, or arrive, will be known as platform points in this text. Again, there may or may not be a physical platform next to the track, but the concept is important in signalling, since this is where train routes begin or end.
Entry routes go from outside the station to a platform point. Exit routes go out of the station from a platform point. Certain combinations of entry and exit routes combine to through routes where a train may go through the station without stopping. Entry, exit, and through routes is collectively known as train routes and are signalled with main signals.
Shunting routes go from somewhere in the station to somewhere else. They are signalled with shunting signals. Most marshalling take place without routes in which case the shunting signals are cancelled.