I bought a 60 trolley on the bay for the chassis, but when it arrived it looked in pretty good shape. I decided to try to resurrect it. I put in on my test track for a quick check and it started to smoke. Time to dig in. I've completely refurbished 3+ trolleys, so I'm pretty comfortable with taking it totally apart and rewiring what's necessary (short of rewinding the field coil and armature). It was in pretty bad shape with 50+ years of caked on grease and disintegrating wires. Amazingly the brushes were in great shape. I cleaned it all up, lubed it, rewired the track rollers and light, and put it on my test setup (alligator clips, no track) with power coming straight from a KW transformer. The motor and light worked really well in both directions. Great, time for a track test.
I put it on my track which is powered by a ZW, with a kill switch when shorts are detected. It tripped the short switch in both directions. I took it apart again, made sure all connections were secure and no exposed wires were touching anything. Again, it worked fine with power from the clips. When I put it on the track, it again tripped the short switch. So I reset it and tried to power it up slowly with the ZW handle. The light came on at low power and got brighter as I increased power. The light would stay on at that point and not trip the switch. But when I applied more power to get it to go the switch tripped.
The armature seems to be in the worst shape. You could see some rust on the outside of it. I rubbed it off the best I could. Would that be the source of the short? I do have an ohm meter, but I'm not real good at knowing how to use it.