my three, (red,black and yellow) all run fine on my modern Hornby set track. agreed the wheels do seem to need cleaning regularly. I have seen the ones on E Bay, I do think that some vendors do try their luck. I have never spent more than £15 on one. The yellow one is suppose to be the rarer one as it was only sold as part of a set. There was also a purpose built snowplough for it but they are like hen's teath. good build BTW