Illinois Zephyr

If you have enough room for a loop-to-loop setup, obviously the single train set could be used multiple times, so too if you have a bidirectional train set with a cabbage or cab car, as trainsets are all typically oriented in the same direction.

Alternatively, you could take a page from the Carl Sandburg and Illinois Zephyr, which deadhead from their last station stop, Quincy, Illinois, across the river to a yard in Missouri, and lay over on a single dedicated spur.

Maybe it's a little larger and more complicated to pull off than a DMU, but especially if you love the idea of the Machman, Siemens, Charger, and Midwest Venture Coaches, or hopefully any moment now in Arrow trainset, It's not entirely unprecedented to shuttle a modern passenger train set onto a switching area and store it on a single spur.

Amtrak trains on a shelf switching layout? I can't wait for the day.