Another thing to watch for with Atlas code 83 switches if that some of them have the frog sitting too high - I first discovered this when my friend cn nutbar brought over some of his brass locos to run. Most of them would stall on certain turnouts, and I finally traced this to the frogs being higher than the rest of the rail. When a couple of the locos' drivers rolled onto the unpowered frog, all of the drivers were lifted from the track on that side of the loco, breaking the current flow to the motor. My plastic steamers, which pick up from all wheels, didn't experience these problems. I probably should've powered the frogs when the track was originally put down, but my simple solution was to make a few passes with a mill fill over the offending frogs, making sure to vacuum up the filings before running trains.
Everybody should have a wheel and track gauge - you'd be surprised at how many cars and locos have out-of-gauge wheelsets right from the box.
Wayne