@Bill N posted:Tom, for purposes of my question I was avoiding drawing a distinction between which line was considered the siding and which the main and just said there were two through tracks. However let's assume that the line closer to the station was considered the siding and the one further away the main. That way the cars spotted at the freight station are on the siding rather than the main.
See my first post in this topic about the siding not normally intervening between the depot and the Main Track.
But let's say there are two Main Tracks at this fictional station. In that case, a local freight might do freight house work off of the Main nearest the depot, but must not block passengers crossing that Main Track for passenger trains using the other Main Track.
And, as I previously said, freight cars would never ever be left unattended on a Main Track in order to do freight house loading or unloading. That is extremely unsafe and against operating rules, because -- sooner or later -- there would be an incidence of the cars rolling away. Lots of things could go wrong, such as vandals releasing hand brakes, crew members relying on air brakes and then the brakes leaking down to zero psi, crew failing to test hand brake before leaving cars and then having the hand brake be ineffective when the air leaked down to zero. Extremely unsafe, as proven by disastrous incidents.
In railroading, trains or engines must have some form of authority to (even Yard Limits, which is not on yard tracks, but is a form of authority for use of a Main Track without having to talk to the Dispatcher) occupy a Main Track for any reason. Auxiliary tracks (sidings, spurs, yard tracks, etc.) can be used without authority. So, it would be fine for a local freight crew having authority to use the Main Track, to stop and switch a station, or do station freight house work, off of a Main Track. Cars uncoupled on the Main Track would have to be secured by use of hand brakes (The engine might have to leave part of the train on the Main Track while doing station work in spur tracks.). But they could not leave cars on spot on a Main Track for freight house work and move on to the next station. If the siding was actually nearest the depot, then cars could be left on spot at the freight house, unattended, with derails at each end of the siding placed in the derailing position in case the cars rolled away.
Model railroading is so much easier than the prototype. 
