1033 diode

Hello all, I have a model 1033 transformer that keeps exhibiting the infamous whistle "rectifier" smoking. I've replaced it twice already and has just gone again. :( I'm using a 6 A rectifier , installing it with the anode facing terminal "U". Any ideas as to why it keeps toasting on me? Any...

I have an old 1033 that, when the whistle switch is turned, causes the train to pick up speed instead of blow the whistle. In a few other threads on this and ctt site it was advised to swap out the old rectifier with a 5 amp diode. So, I went to RadioShack and bought a 6 amp rectifier diode (all...