What can damage a Lionel train? Neglect and abuse, basically. When well cared for, they’re pretty bulletproof.
There’s not a lot that can damage a Lionel train, as long as you store it in conditions that wouldn’t make you terribly uncomfortable, run it within spec and maintain it occasionally.
Moisture is probably the first problem that comes to mind, since that causes corrosion and rust. Store it indoors in a conditioned area and it will be fine. Store it in a toolshed, and it won’t do as well. Here are some more tips for storing Lionel trains and track.
Lack of lubrication
Not lubricating a Lionel train properly will eventually catch up with you. Unless you run them heavily, you really only need to give them a couple of drops of oil every few years. The cost of not doing it is high, as it can burn out the armature due to overheating. That’s a costly repair. If it squeaks or squeals while it’s running, it needs grease and oil. Here are some tips for lubricating Lionel trains.
A costly Lionel train runs like a Swiss watch. The more common ones run more like a nice Timex, but still, if it’s herky jerky or looks like it’s working hard and the problem doesn’t go away after a couple of trips around the track, something’s probably not quite right.
A big no-no is using harsh cleaners on Lionel trains. For example, even water will wash red paint right off a postwar Lionel train. I’ve done it myself. Water is safe on most colors of paint, but harsher cleaners often is not. If you don’t know what you’re doing, dust the train with a soft paint brush and leave it at that.
Here are some tips for cleaning Lionel trains safely.
Overvoltage. Some early transformers can output 24 volts and most Lionel trains are designed for a maximum of around 20. Run your train with the transformer it came with, and you’ll be OK. If you upgraded the transformer at some point, just go easy on the throttle.
Physically dropping it can also cause problems. Go easy on the throttle around curves, and use wide curves to prevent drops from the table.
Also, when you take one apart for maintenance, take care not to misplace parts. Ideally, sort the parts into a small plastic bin with dividers and label them so you know what they go with. It’s amazing how parts can wander off and it can take years for the parts to turn back up again so you can make the train whole.