Over the years, Marx made electric and clockwork trains in no fewer than seven sizes and two gauges. Depending on how you count Marx train sizes, you can say it was more than that. Here’s an overview of what they made.
If you go to sell Marx trains, correctly identifying the size definitely makes them attract more bids.
In the 1950s, Marx and Lionel took turns being the biggest toy company in the world, largely riding on the popularity of O gauge trains. Neither company particularly liked the other, but both owed some degree of their success to being compatible with one another. Because of their interoperability, the two makes of trains are frequently compared and contrasted even today.
For a while in the 1970s and 1980s, Lionel used DC power in its least expensive O27 electric train sets. They stopped this practice in the mid 1980s, but there are still plenty of those sets kicking around in basements or attics and on the secondary market. They tend to be very inexpensive, especially compared to new sets on the market today.
Here’s how to figure out what you have, and track down a suitable replacement. AC and DC power supplies are not interchangeable, and you can seriously damage your train if you use the wrong kind.