Dump Trucks and Wheel Loaders - Model Railroader Magazine

One way to backdate a wheeled loader is to take the enclosed cab off. Those were around, but most operators of that era tended to eat a lot of dust. Yes, generally smaller equipment. I'm unsure when ROPS (Rollover protection) was required, but there still were quite a few loaders still around without a heache rack in 1970. They thinned out a lot over the course of the decade, so were getting to be unusual to see by 1980.

The Woodland Scenics Tracked Loader is older vintage, but still could've been working in the early 70s, but rarer towards the end, except parked behind the shop more often than not. Remember that having some older, out of service equipment around is another way to date things.

Trident makes a heavy duty forklift (729-90094) that shows some promise to being adapted to being a small loader, altyhough I haven;ty seen one.

GHQ has a loader (284-61003) has a cab, but looks like taking it off could backdate it .

I think you've identified one of those prototypes that would seem to be a big hit, since they're common at around railyards, as well as making nice flatcars loads. There's nothing quite right out there, so if someone brought one to market and hit the right price point, they'd have a winner on their hands.