On the Yehaw (Yahoo!) N Scale List Marty Young posted that he had recieved his second run locomotives, that the wheels were the same oversize Flanges on tenders (which is true) then went on to say a friend of his had replaced the MRC Sound Module with a LockSound Mini module. Reason for this was after four hours of continious running the original had failed and Young went on to say that every Challenger in his club had had the modules fail after four hours of continious use. Anybody else out there heard of this problem occurring? I have run my first 2 locomotives quite a bit,but certainly mot continiously for four hours. My 3rd loco is just getting broken in. If I take these to the Wasatch Division NMRA Train Show in November should I rest them for awhile between say half hour runs? Would turning the sound off for awhile prevent this or is just having the loco running going to cause a failure? I 'am running them in DC and I assume Youngs club is usuing DCC . Nate Goodman (Nato). Salt Lake, Utah.