Hello. I have a Pennsylvania flyer 6-30018 that I have been running for the past several years. This year my tender whistle will not work. I read some other topics and tried cleaning the track and cars, no good. Also tried reversing the polarity. This actually made the whistle run constantly. So I know the whistle will work , I just can't figure out what's wrong. The transformer is a model cw80. The train operates but I notice the headlamp seems to flicker. Any thoughts?