...gotta be some way of powering it. Cable cars work as do electric vehicles that run off suspended power lines. Just theorizing here.
...wonder if it could work like a hand powered railroad cart

It would have to be smaller and capable of pulling a couple of sleds behind it. Or ya could put multiple hand powered carts in the mix.
Maybe the carts and the system were already in place to support the welders and their equipment before the was.