Farish class 24 problem

[D9020 Nimbus]

I have two Farish class 24s that have sat idle for a little while. Both now exhibit the same problem: they make a thump-thump-thump noise as they move along, the frequency of the thumps being proportional to the loco speed, and move very jerkily at low speed—the jerks being in time with the thumps.

 

A third class 24 is fine, as is a class 25/3 (Bachmann/Farish, but the old body moulding) which has been idle for at least as long (and stored in exactly the same conditions).

 

Is this some manifestation of the split gear problem? It doesn't seem to fit the usual symptoms. The thumps are quite loud.

 

All the 24s are from the first batch. I can't recall reading about 24s with split gears before.

 

Any ideas?

[Pyewipe Jct]

I'd suspect a split gear, unfortunately - I recently bought a cheap Class 24 which was advertised as having a split gear (which surprised me a little, too) & it had a loud-ish 'clunk' on each axle rotation. In the end, it wasn't a problem for me as I was fitting 2mm drop-in wheelsets, but there definitely are some split gears out there on the 24s.

HTH,
Kevin