If you worked inside, you would know they feed the belt in the center.
The set up is one side with single bays for the trailers (which is called the back wall or CPI or CPU), conveyer belts go into the trailer and feed onto the sort belt which is in the center of the building. Then there are two other conveyer belt lines where the package cars back up on either side of the belts, those belts then feed to the sorters, zig zagging through the building. I work twilight, so I have never seen the loading of the package cars. Some of the trailer doors are for load (I guess those would be the feeders? The trailers that go onto other hubs), so there are three unload trailer bays and the rest are load trailer bays. There can be an unload and a load trailer in side by side bays. Three doors are designated for unloads on the feeder side. One of those sort belts dumps via a chute right onto the small sort line. I am not sure how many employees are there. Generally there are four to five of us who do the twilight package car unload. I don't know the sizes of operations so I can't really compare.
