"HO trains weren't designed to run 8 to 10 hours a day", he says in the piece. That's probably true, but a lot of O gauge trains would have a tough time with that schedule, also. The key is constant maintenance and swapping out equipment.
This layout is beautiful and impressive, but it always seems much more "delicate" the the old 2-rail O Gauge layout. Of course, I grew up with the old layout, and I would make a beeline for it whenever we visited the museum. I used to go up in the balcony and look down on the old layout, watching the Warbonnets and the blue/yellow F -units make the entire circuit.
Make sure you view the engineer's view video at the end of the piece. You can see a number of the museum's other train displays, including a rear view of the #999.