I have replaced the rectifier disk on a couple of transformers with diodes. One is a Lionel zw with the heavy duty stud diode rated at 40 amps and a tw with a 6 amp diode. They work great at this seems to be what most recommend when replacing the disk. I read some old threads that said they would destroy the switch contacts in the the transformers in time. Has anybody seen this happen in the real world or is this academic banter? This is what most of the transformer repair gurus recommend.