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Installing trucks on junker train cars

Sometimes a train car breaks, and sometimes you get a good deal on a train car that’s missing its running gear. Whatever the reason, sooner or later most hobbyists find themselves needing to attach trucks to the underside of their train cars, and if they’re like me, they soon find that using a regular nut and bolt doesn’t cut it–the nut works itself loose after a few times around the track, which leads to wobbly running, which leads to derailments.

There’s a solution other than expensive riveting tools, if you’re just interested in making cars run well, rather than restorations that are as historically accurate as possible. For about 15 bucks, you can get enough parts to do 50 cars.

The key, rather than using an ordinary nut and machine screw, is to use what’s known as a stop nut, which has a nylon insert in it that makes it highly resistant to loosening.

The key is knowing what size to get. You want something that fits tightly, with as little play in it as possible.

Postwar and modern Lionel, as well as most modern competing brands like K-Line, use an 8-32 machine screw and stop nut.

For Marx, American Flyer, prewar Lionel, and most other prewar brands, use a 6-32 machine screw and stop nut.

The links I provide are for boxes of 100, priced at approximately $5 each. The shipping rates are hard to find, so here’s a link. A good hardware store will have machine screws and stop nuts, but they usually don’t sell them by the box. If you’re going to do more than a couple of cars, it makes sense to get a box, so you’ll have plenty of parts on hand.


Apply a bit of Labelle #106 grease to the top of the truck, and put a drop of light oil in the hole in the base of the car. Thread the machine screw through the base of the car and into the truck, then spin the stop nut onto the screw and tighten it down as tight as it will go. Then back it out, a quarter turn or so at a time until the truck will turn freely but won’t wobble. Then apply a drop of oil at the edge of the screw head and at the edge of the nut and turn the truck back and forth about a dozen times to work the oil into the joint.

Eliminating the wobble virtually eliminates derailments–so much so that I know one hobbyist who removes the factory rivets from every car he gets his hands on and replaces them with a screw and stop nut. For what it’s worth, he insists he gets no derailments, even when he does an O27 s-curve–something you should never do–or runs backwards over an O27 switch.

While you’re messing with the trucks, lubricate the wheels. Spin each wheel and see if the whole axle turns, or just the wheel. If the axle turns, put a drop of oil on the tip of the axle, where it meets the side of the truck. If the wheel turns individually, put one drop on each side of the wheel where it meets the axle. Spin the wheel to distribute the oil, then put it on the track. My new favorite oil is Quantum Hot Sauce. Yes, it was designed and marketed for fishing reels, but something about the additives in it makes the wheels spin more freely than any other oil I’ve tried. And since it’s designed for fishing reels, it won’t harm the plastics in trains. The red color makes it easy to see when you’ve applied a single drop and stop there. A little oil is good; too much of it causes more problems than it solves.

Sources for inexpensive cars

I’ve paid as little as 50 cents for loose bodies at train shows. Running gear costs more. Sometimes it’s possible to get plastic trucks with non-operating couplers for a dollar or two apiece. Nicer trucks run more like $4 or $5 apiece. I always look for loose trucks at train shows and buy whatever I see, because it’s always easier to find freight car bodies than it is to find the trucks that they run on.

When I’m really itching for trucks to get a car to run, my local train store will sell loose trucks. He usually charges about $3 for the cheaper trucks with non-operating couplers.

I’ve put together cars using junk box bodies and trucks for as little as $3, total. That’s a nice bargain considering the very least expensive O27 freight cars start at around $25 new, today. At the $3 price point, I don’t mind letting my 3-year-old son play with them more or less unsupervised, as long as they’re all plastic and I’m sure there’s no old paint on them that could contain lead.

And my bargain car with the trucks attached with machine screws and stop nuts will track better than that $25 car.

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