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. Trying to run a DC train on AC results in a train that won’t move and makes a ton of noise.
Why Lionel used DC
The trains that made Lionel famous ran on AC voltage with AC transformers. In the 70s and 80s, Lionel switched to cheaper DC motors. It also let them switch to cheaper DC power packs, which are made in huge quantities since HO and N scale trains also use them. The change probably let Lionel sell sets for 40 percent less than the cost of a traditional AC set.
The problem is this killed backward compatibility with the millions of Lionel AC trains out there. Eventually Lionel decided that selling cheaper sets in discount stores wasn’t worth it. When Lionel sold trains at Target during the previous decade, they were the same sets they sell in hobby shops.
There’s nothing inherently wrong with these older, cheaper Lionel sets. They work fine, and they look just like a Lionel from the 1950s because they’re made from the same molds. They make fine trains for your Christmas tree or your Christmas village. Lionel just put a different motor in them.
How to tell DC from AC
Often, the transformer will say whether it outputs AC or DC. That’s your first clue. If the device actually says “transformer” on it, it’s more likely it’s AC. Most train manufacturers, refer to their DC counterparts as “power packs” or some other similar terminology.
Sourcing a replacement DC power pack
If you have a DC power pack, and you’re sure it’s dead, you can replace it with any DC power pack intended for HO scale trains. The power packs supplied by Lionel weren’t anything special–if they even said “Lionel” on them, someone else made them and put the Lionel name on them.
Sometimes Lionel didn’t even bother with that, just packaging someone else’s product along with their trains.
This Model Power unit is one example of a suitable DC power pack that I was able to find quickly online. Most hobby shops that deal in trains will have a selection of them, and some even have used ones. Used HO power packs tend to be very inexpensive, sometimes selling for as little as $5.
Converting Lionel DC to AC
If you prefer to make your locomotive compatible with traditional (as well as newer) Lionel so you can use a traditional AC transformer, you can convert it to AC using these instructions, courtesy of Lionel itself. There’s no modification necessary to the track or the cars.