I DCC'd a Hornby 2P (or 4f, can't remember which) with traction tyres, and spent ages poking and prodding as it worked when it felt like it, (I have previously done other similar locos with no probs), and when I removed the tyres it worked fine. I couldn't figure out why, ( sometimes fine on rolling road, not on track, and vice versa), but just accepted it. If its easy to get the tyres off give it a try.