I've seen the Shays at Roaring Camp, near Santa Cruz.[1] Good to know they are still running. All those huge open bevel gears! It's all-wheel drive, including the tender, using a long drive shaft with universal joints and splines, all out in the open exposed to dirt. At least on a Shay they're easy to reach. Somebody probably has to grease the drivetrain before every trip.
[1] https://roaringcamp.com/excursions/redwood-forest-steam-trai...
> ...all out in the open exposed to dirt...
Back in the day, I suspect they'd have covered much of that with tin* or wood, to cut down on cleaning, maintenance, & wear.
*Meaning "cheap, thin sheet metal"
I strongly suspect that they used oil, not grease, so they could flush the dirt out of the gears, and that this would have been done very frequently.