Here are a couple of the American Flyer cars with the Lionel cars I worked on. I didn't need to do anything to the 3207 gondola. I couldn't improve it's appearance much. It will need some wax eventually. The caboose needed cleaning and polishing. I also needed to do a minor repair on a handrail. The Lionel 1717 gondola had a very rusty frame, which I soaked in Evaporust, Dremeled and then repainted. The 1719 has my homemade roof installed.
The caboose has the pickup roller, but not the light socket. Will an S gauge socket work? I found an original, but the cost is half the price of the car! I can get a modern replacement for pennies, which should work and not be very noticeable.
George
