Transformer Suggestions

I expect you to get quite the range of answers on this one.  I'll recommend a post war KW or ZW just because these are tough transformers that can be had on the cheap.  If you want a bell function you'll have to go with a modern transformer, or purchase a bell activation button. (about $20 at your LHS)  If you're only running one train, even your little 75W transformer will probably do the job, but anything in the 90+ watt range will be more than enough.  a pure sign wave transformer will run anything, but some early MTH engines don't like the chopped output on some modern transformers.  These problems can usually be solved by running lighted cars on the same track.  

JGL