Since no one has replied yet, I'll give it a guess. If nothing else you will get a bump up.
I don't know, but the top picture looks like better quality and possibly needing two wires, one wire to each pick-up roller. The bottom picture looks like a little less quality, rollers look smaller (I can't exactly tell from the picture?) and possibly they are tied together requiring only one wire. So maybe cost savings?
The Lionel engines I have so far use the 2 pick-up rollers and the rollers appear to be of very good quality. Other guess would be the bottom picture was an earlier design that caused a problem and the top picture was the improved version with better operation and more expense?
