There is some unfortunate misinformation circulating on various train forums. I first read this misinformation in the outstanding book by Peter Riddle, Trains from Grandfather’s Attic, published in 1991. As Classic Toy Trains editor Bob Keller noted while we were finishing up my article late last year, incorrect information in print lasts a long time. A very long time, sometimes. Lionel 1121 switches and Marx trains are rumored to get along famously. I am sad to report they do not.
They actually work well approximately 3/4 of the time. In three directions, the Marx “fat wheel” passes without incident. But in the fourth direction, the locomotive bounces. The bounce is devastating when a 2-4-2 locomotive, such as the 999, tries to pass through because the bounce almost always causes either the front or rear truck to derail. The cheaper and simpler 0-4-0 locomotives actually fare better, making it through in that direction perhaps half the time.
I learned this the hard way. One Christmas, I set up a double-reverse layout with two Lionel 1121 switches, intending to run a Marx Canadian Pacific consist pulling as many 552 gondolas as I could round up. Ultimately I ended up having to sub in a Lionel locomotive, because every third or fourth pass through the layout, I’d have to deal with a derailment.
I understand the appeal of the 1121, because it’s easy to control with an insulated rail, it’s common, relatively cheap, and works well with any other make of O27 train.
And perhaps in some situations, it would work fine, even with Marx. If your normal routing never takes the train through the bad direction, you may be able to get by with 1121s. If you note which routes give a Marx locomotive trouble and avoid them when running those, you’ll probably be OK because it does work very reliably in three of the four possible directions. The 1121 is a quality machine; it just wasn’t designed with the quirks of a competitor’s locomotives in mind.
Unfortunately I’m not in position to test which direction gives problems, as I sold my 1121s soon after I learned about the issue and used the money to buy some Marx switches. I think the curved leg works in both directions, but the straight leg only works in one direction.
Of course the later-postwar Marx locomotives with a double reduction motor work fine with virtually any Lionel switch. So one solution, if you want to use Lionel switches, is to swap double-reduction motors from Marx 400 and 490 locomotives into the earlier tinplate locomotives. The swap only requires you to remove two screws, and it’s easily reversible.
Or better yet: Wire up some Marx 1590s to behave like Lionel 1121s.