I have an original, and I had the Conosoli gold set, that I sold a few years back. I've had no heat problems and no problems running on O-31 track with mine.
They're great trains, and run well, IMO. I won't be selling my original any time soon.
If anyone here does have a supplier for diaphragms, I'd like to purchase a couple more as spares.
Also, recently I have been looking for information on a Western Coil device made for the trains called the Midget Dispatcher. It was supposed to be a rotating drum that could control accessories and trains. I've seen only limited information on one, and I think a picture of a real one.
If anyone has any info on this, I'd appreciate it. I believe that General Trains used/marketed the same device under their brand.
I'd like to find one at some point, just to see what it actually did and how it worked.