This also happens, of all places, in Washington DC for trains stopping at the lower level or tracks 7, 8 15 or 16 on the upper level. Of course, if it's a through train, the station dwell time will be long enough because they're switching locomotives, but it's quite something about how long it takes to unload a fully packed Northeast Regional arriving from the north when only 2 or 3 doors of an 8 car train are open. For an interesting comparison, the MARC conductors make it their business to open all the doors when they come in on the low platforms in Washington, but the Amtrak conductors don't. It may take a little while, because there are only 2 or 3 conductors, but the trains unload faster than they would if only 2-3 doors were open.