In the early 1950s, Lionel had two different standards for the couplers on its train cars. “Serious” sets used its knuckle couplers. Entry-level, or “Scout” sets, used one-piece couplers that came to be known as “Scout” couplers. My Dad had cars with both types of couplers in his collection.
Once I got Dad’s set running, I found a Marx car on eBay that I absolutely had to have–an operating Missouri Pacific cattle car. Marx used its own couplers. So how to get both types of Dad’s cars, plus my new Marx car operating together on the same train?
Enter the conversion car.A conversion car is just a car with two types of coupler on each end. I went to Marty’s Model Railroads in Affton to get mine made. Ideally, I’d have done a Marx-to-knuckle conversion car and a Marx-to-Scout conversion car. Then I could convert either type to Marx, and if I wanted to convert Scout to knuckle, I could just use the other two conversion cars. But Marty only had one Marx truck, so I got a Marx-to-knuckle and knuckle-to-Scout made. One could also make a makeshift Marx-compatible coupler with a Lionel truck that lacks a coupler but has a rivet hole (such as those used on the back end of some Lionel cabooses) and a wire Marx coupler substitute.
The only thing to say is to not use a collectible car to make your conversion car. There’s so little market demand for Scout cars that you won’t hurt their value of most of them by making them into conversion cars, and the same holds true of most Marxes. I used cars out of Marty’s $10-and-under box. I’ll also add a suggestion Marty made: Use an open car, like a gondola or a hopper, that you can put a load in to weigh it down. I find my conversion cars derail much less when loaded down with some weight. Even just a film cannister filled with pennies is enough to make a difference.
In the 1950s, Lionel’s knuckle coupler design gave the best combination of realism and reliability, but at a higher cost. Marx’s design was reliable and very inexpensive, but didn’t look very realistic. The Scout design looked realistic and was inexpensive, but wasn’t as reliable as either Lionel’s knuckle coupler or Marx’s tilt coupler. Today, the difference in cost of manufacturing is probably negligible, and people aren’t so concerned about cost anymore anyway.
Serious hobbyists prefer the Lionel knuckle couplers, and for the most part that’s all that anyone makes anymore. But if I like a car, I’m going to buy it, regardless of the coupler, and I want to be able to use basically whatever combination of rolling stock I like.
I’m not sure what that makes me, but conversion cars let me do it, and cheaply.