I was wondering if anyone has seen this. I have one of the original bicentennial trains put out by Lionel with the GS-4 Steam engine. I purchased it off of ebay many years ago and finally am getting around to cleaning it up and making it run worthy. After a good cleaning and lube, I was running it last night and smoke started to come out of it, the problem is it doesn't have a smoke unit! It's one of those split chassis with the motor built into side frame (I think its called a pancake motor?) Here's the thing there is a 42.2 Ohm 1/2 watt resistor soldered between the right and left sides of the chassis. It was the cause of the smoke, but what is it used for? I've never seen this before and I have plenty of old engines. Any help would be much appreciated.