Niles Canyon Railway sometimes runs push-pull excursions... they can't turn at the terminals, and head-end power looks good in both directions.
Push-pull is not a historical scheme on the D&S either, but it also makes sense in these COVID circumstances to have head-end power with an extra-long passenger consist. 25% capacity is prudent for winter excursions with cold temps and closed windows.
With steam locomotives, I assume the engine crews stay on the same locomotive? Or does the senior crew swap to the head end? I wonder if 101 & 107 could push/pull MU with a single engine crew? Sorry to think like a transition-era beancounter... the Polar Express is rightfully steam.