Stuart Firth
Hi David I’ve hesitated to respond until now as I have never looked at one of these, so my comments would naturally be somewhat general. However they look to be, essentially, kit built loco’s with a white metal body and brass chassis. Practically speaking it should be possible to fit EM Markits axles, though of course there will be a great deal of sideplay, which could perhaps be overcome with plasticard frame overlays. The big thing to check will be clearance, as Romford/Markits wheels in EM may not fit into splashers etc. It should be possible to work this out with measurements. Markits wheels come on and off very easily so careful experimentation should not cause a disaster. As to the gear wheel, you should be able to see if there is a grub screw on it – if there isn’t it will make things a lot harder unfortunately!
Why not post some pictures of the underside ? It will give us a better idea of the set up.