yesterday i was visiting a local antiques fair, and i found something very unexpected.
two meccano pulleys, the same as they used for bessie the engine’s driving wheels in chigley!

i would have gotten some of the smaller wheels too, but the chap i got them from only had one of the eight i’d need.
i don’t know if i’ll ever attempt a replica, but they’re good to have around as a “just in case” ;]