I bought this model 2nd hand off eBay some years ago, but I've never run it much, and I haven't got round to installing a decoder, because it developed A Problem not long after I got it. 

Basically, when it runs, it clicks and when it goes round bends it screeches. The click seems to be located in one of the bogies and the coupling at that end jogs up and down in time with the click. I suspected a broken gear wheel somewhere and filed it under "probably very difficult". Fast forward to earlier this week and I was admiring the same model on another swiss N layout here so I decided to look into the problem. If you watch the first video with the sound up you'll get the idea. 

So I removed the offending bogie and managed to strip it right down. Odd, there's no sign of any damage to the gears at all. 

But on reassembling and running the bogie by hand, it was now binding quite severely, and when I try to run the model it's not good at all, as the next brief video clip shows. The worms are not turning and the motor gets hot and smelly very quickly, so it's not just that the worms aren't engaged. Something is locked.

Not sure, what to try next. It's just possible that the problem is with the wheelsets and I didn't notice at the time (the click appeared to be once per revolution of the wheels) so I'll check those again when I get time. But if anyone has any thoughts, suggestions or actual experience with this problem, I'd love to hear from you.

Stay safe

Keith