When train is shorter than station, the train doesn't interact all of the station modules.
In this screenshot my train (which transports recyclables pressed) has 6 cars (1 loc - 4 wagons - 1 loc) and station has 10 modules. (2 locs - 6 wagons - 2 locs)
I expected my train will go back and forth to interact all modules of the station, but in game it just interacted only 4 wagon modules and the remnant 2 modules just store cargoes inside.
I think it'll be better if the train interact all modules of the station.