What is the minimum track radius for an N-Scale 2-6-6-2? I'm using the 15 degree Kato track and the engine seems to slow down, almost sticking in the curves.

Who do I turn to for repairs on a Williams engine? Over the past 2 weeks, I've left 2 e-mail repair requests and 5 different voice mails on the Customer Service Manager and operators phone at Bachmann and have yet to get a reply from anyone.