I put Bullfrog snot on my steamers and while it improved pulling power it lead to poor pick-up and on some locos bad running what I do now is put lead in my steamers. Just ask Warbonnet how heavy Tornado is. I got a hornby Duchess of Sutherland at the weekend (I blame Warbonnet=))) and surprisingly she pulls 10 coaches around my layout no problem but when it comes to large wheel steamers and a helix forget about it, no matter what you do they don't like them, its time to play banker.
On the 201 issue pull the diesel tank of and fill with lead and super glue and then glue the tank back on. Bingo more traction still not as good as the 66 though. Speaking of which I also got a Bachmann 66 at the weekend (Warbonnet again ) took it out of the box put a Bachmann decoder in and hey presto front/rear and cab lights all work. Its also a smoother runner and better puller out of the box than the 201 I hope we don't have these problems with the forth coming 071 and if only 4 axles are powered on it, its pulling power is going to make the 201 look like Arnold Schwarzenegger at a anabolic steroid convention.