You're correct wrt the midnite hour. But similar jams occur around 10 AM and 4-5 PM - Zephyr time if it's near schedule, plus a Cap Corridor train somewhere around those times, and the afternoon SJ departure. A Market would certainly be open then. And the southbound Starlight (should be 6-630AM if on time) is usually somewhat late, so it would be coming in while the morning rush of Cap Corridor trains and the morning SJ departure is around (630-8AM), which is also when a Market would be starting up or at least having deliveries arrive. Could get interesting.

If you count each arrival and departure as a train, Sacramento has 32 trains on weekdays (24 Capitol Corridor, 4 SJ, and Starlight and Zephyr passing through with stops). This in a 4-through-track station that, for the short California trains, can be split to handle 2 trains at once, and which operates (except for the Starlight and Zephyr, and one Cap Corridor schedule AM and PM) as a terminal rather than a station. Trains that blow their schedule badly for any reason can mess things up. At least the freights now have bypasses, so they don't have to run through the station tracks themselves. Oh yes, and a crowd of Amtrak buses that meet Cap Corridor and SJ trains, and buses from Stockton for the other 8 SJ runs (4 round trips to Bakersfield from Oakland), and other SJ connections, and a couple of RT bus lines and the Gold Line light rail (light rail every 15 minutes during the day). It can be a busy place at times.

It's not unusual for the waiting room - the big, old one with pews with radiators between the backs that seems to have been under renovation for most of the 15 years I've lived in the area - to be nearly full for several hours a day. Where are they all (and not all of them are homeless campers!) supposed to sit after Amtrak gets moved into former offices and snack bar, and the waiting room (which is where I presume it would be) gets turned into a Market?