Q: I have five modern-era cabooses, four Lionel and one Atlas O, and I would like to add interior lighting to them. How do I do it?
A: The first consideration is finding bulbs that glow warmly without getting too hot for the plastic caboose bodies.
Lionel uses several different types in its contemporary illuminated cabooses. Most train parts dealers can provide them, along with the appropriate sockets.
Then you will need a truck-mounted pickup roller of some kind. If you are lucky, the dealer might be able to supply one that will snap into place on one of your existing trucks. Otherwise, you will have to buy a new truck with the pickup-roller mechanism attached. One of the wires from the bulb socket goes to this pickup.
The other wire must be attached in such a way that it completes the lamp circuit through the car wheels. For cars with metal trucks and frames, this is no problem; simply attach the wire anywhere on the car frame. For trucks that have plastic side frames, you need to find another way to get the power from the wheels to the bulb socket. Lionel often uses copper wipers against the axles to accomplish this. Your parts dealer may be able to provide something that fits on your trucks or new trucks can be installed.