Do they back into the other loco and connect? Or do you disconnect, move that loco forward and connect with the other loco. Or do it both ways depending? Is there some safety reason I cant back up my ore cars right to the main loco with my little local switcher, or do I have to drop off the car free?
It is far more usual to assemble an entire train, including caboose, and then back the road loco onto it, couple, connect the air hoses, open the angle cocks, pump up the train line (which, on a long train, can take a while!) and perform a standing brake application/release check.
If, OTOH, the switcher is simply adding a single car or short cut to a through freight, it would usually stop short of coupling and return to its stub. Then the road crew would back down, couple up, back farther to recouple to the rest of the train (which might be just a caboose or a half-mile of additional cars) then pump up and check brakes as described.
And now you know why something as simple as adding a car or two to a way freight takes a prototype crew so darn much time.
Chuck (modeling Central Japan in September, 1964)
In this case its just one or two ore cars being pulled out onto the main by a local switcher to be attached to the main train. After the transfer, the main pulls away and the switcher then goes back into the siding. Its a facing point turnout so the main cant back in there and pick it up.
When I worked on the railroad there was work rules that govern enroute switching EXCEPT for interdivision transfer trains that dropped off or pick cars up at smaller out laying yards…Also a road crew was allowed to double a train in or out of the yard…However,it was the yard crews job to add or remove cars from a train at a major terminal…