This is NOT another thread about track cleaning. There are several threads concerning that and I've read them all so please don't feel you have to groan out loud when you read this! 
I have come across something that's to do with track cleanliness that I don't understand....
My Bachmann 0-4-0 gas loco started bunny hopping. OK, I hadn't cleaned the tracks so I expected that to happen sooner or later.
I stopped running it and promised myself to have a look at a later date. When I got round to having a look, I saw that the off-side rear wheel (that would be near-side rear to US members!) was thoroughly caked with the black gunge that accumulate on every track (even when you don't run live steam) but the other 3 wheels had hardly any deposits at all!?!
It's only idle curiosity on my part but I really can't understand why 1 wheel would grab the gunge and the rest didn't.
If you've got any ideas, please tell me

I have come across something that's to do with track cleanliness that I don't understand....
My Bachmann 0-4-0 gas loco started bunny hopping. OK, I hadn't cleaned the tracks so I expected that to happen sooner or later.
I stopped running it and promised myself to have a look at a later date. When I got round to having a look, I saw that the off-side rear wheel (that would be near-side rear to US members!) was thoroughly caked with the black gunge that accumulate on every track (even when you don't run live steam) but the other 3 wheels had hardly any deposits at all!?!
It's only idle curiosity on my part but I really can't understand why 1 wheel would grab the gunge and the rest didn't.
If you've got any ideas, please tell me
