So, do I have this straight? I'm pretty sure that's the wye I see on GoogleEarth about 2 miles south of Union Station. The Empire Builder would just pull ahead from the station to get turned around to head north again. But the Chief and the Zephyr would have to back up the 2 miles to turn around, and then back up 2 miles again into the station. Right?
Another question. If there's no need for repair or anything, are the very same cars likely to stay on the train for a many, many round trips?
When I last took the LSL, it would pull into Union Sta. from the South onto one of the few "thru" tracks on the east side of the platform area (ie. goes all the way through both North & South track areas of the platform). Not sure if that track exists anymore. I would imagine that the train gets turned either via the Wye or another means before boarding again.
In re: what you see on Google Earth, I think it could be used for that (ie. turning trains around), but I also think that's the main turn for the BNSF tracks that go west/south west into Naperville, etc. (e.g. the route taken by the SWC), and the METRA commuter trains (ie. the old "Burlington Northern" route to Aurora).
The AT's consist is *not* turned around with a Wye, per regular procedure. When it arrives in LOR, the platform is long enough for the entire pax, portion of the consist to remain in tact. In fact, there are fixed placards posted on the platform columns indicating where each car is located (e.g. 53XX), as there are in SFA (52XX), although the pax. consist in SFA is split in two, due to the shortness of the platform. The engines are decoupled and moved onto a side track and then shuttled to the opposite end of the pax. consist and re-coupled. The car containers, of course, are decoupled from the train set prior to the arrival of the pax. portion into the station itself and split as required for the ramps.
What is interesting is that it's set up such that the cars, inside the containers, are always pointing in the correct direction for the ramps, such that they can always roll forward, and don't have to be "backed in/out." Somebody was using their head.
When underway, however, they (cars in the containers) are facing in the reverse direction of train travel.