Are Lionel trains AC or DC?

Last Updated on October 6, 2022 by Dave Farquhar

Are Lionel trains AC or DC? That’s a trick question. Traditionally, Lionel trains run on AC but there are exceptions. And even when Lionel trains run on AC, they sometimes do some DC trickery. Let’s explain.

Traditional Lionel trains from before 1969 can generally run on either AC or DC, but are better off running on AC. Some Lionel trains sold in discount stores in the 70s and 80s did run on DC, as a cost reduction measure.

AC and DC on traditional Lionel trains vs modern

are Lionel trains AC or DC
Traditional Lionel transformers like this KW emit AC power for the train, and DC power for the tender when you use the whistle controller.

Traditional Lionel trains used an open-frame motor that technically will run on either AC or DC. This was important early in the 20th century. Most homes that had electricity ran on AC, but there were some parts of the country that had DC power. Some houses didn’t have electricity. In those cases, kids would run their trains off a car battery, which was DC. That’s clever. Not very safe, and I wouldn’t turn my kids loose with a car battery, but it’s clever.

Now, in the 70s and 80s, things changed. Small, cheap DC motors became available. Lionel trains were no longer the hottest thing going, so Lionel wanted to move downmarket to try to increase sales. To that end, Lionel tried putting cheap DC motors and power packs in their inexpensive trains intended for discount stores like Kmart and Zayre, and even some of the sets they sold through catalog retailers, like the Lionel Laser train. This introduced incompatibility with the higher-end Lionel trains sold in hobby shops, which still ran on AC. It also didn’t revitalize the brand the way management wanted, so Lionel discontinued this practice by the late 1980s.

Attempting to run a DC-powered Lionel on AC causes malfunctions. It’ll make a ton of noise, but it won’t move. If you have one of those trains, power it with an HO scale transformer to keep from burning up the motor.

One downside to using DC on a traditional open-frame Lionel motor is that it can magnetize the reverse unit over time and eventually cause it to stick.

Another downside to using DC is it interferes with the whistle unit in the tender.

The Lionel whistle and DC

Lionel used a clever trick with its whistling tender. Once AC was firmly established as the household standard, Lionel pulled a MacGyver move to control the whistle in its tender. The tender contained an electric motor, a relay, a fan, and a whistle. By injecting DC power on the track in addition to the AC, Lionel could activate the relay, which in turn activated the motor in the tender to blow the whistle. The motor in the engine didn’t mind the DC and continued to run, and the motor in the tender ignored the AC.

The problem with this is that if you use DC power to run the locomotive, the whistle in the tender blows all the time.

Modern Lionel trains and DC

Modern Lionel trains generally use the cheaper DC motors, but include electronics that rectify AC power to DC. In theory these trains should be able to run on DC as well. In practice, I’ve heard people say not to do it, and I’ve heard people say they do it. Having not done it myself, and not knowing who to believe, I recommend using modern Lionel AC transformers on modern engines.

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3 thoughts on “Are Lionel trains AC or DC?

  • April 29, 2020 at 12:24 am

    Modern Lionel gets weird with DC. With the the widespread use of solid state reversing electronic reversing units in the 90’s, lionel began advertising both open frame AC motor equipped locomotives and DC can motor equipped locomotives as “AC or DC compatible,” but only if they weren’t equipped with a whistle or electronic sound system. Electronic sounds included an electronic whistle, which was activated by the whistle button, an electronic bell, which was activated by a second “bell” button that sent a second reversed DC signal to activate a pre recorded bell sound, and later engine noises that matched the locomotive speed. So, while almost all Lionel trains built after the early 2000’s have DC can motors, they have to be run on AC, or it blows out the sound system. The exception to this is the new Command system called Lionchief that they started selling in 2014. Lionchief starter sets come with a simple fixed voltage DC power pack. The individual locomotives come with a paired remote that controls it directly, including speed, direction and whistle and bell sounds. Lionchief engines will work on either AC or DC and will work on a conventional layout. You just have to turn your transformer up to about 18 volts to get sufficient power for the locomotive to run, then you control it with the remote. A couple of years ago they made a number of classic Post War Lionel engines with Lionchief, like the 646 style Hudson and 726 style Berkshire. The seperate sale engines can be switched to run in conventional mode with a transformer.

    • May 1, 2020 at 10:07 pm

      Thanks. The Lionchief was what threw me. Now that you mention it I know it’s Lionchief that I’ve heard some people run on straight 18V DC.

      • May 10, 2020 at 11:20 pm

        You’re welcome. I bought some Lionchief. The starter set locomotives only run with the included remote, but the seperate sale Lionchief Plus engines can be switched to run in conventional mode. I think the advantage over all the other systems like the Lionel Legacy system or MTH DCS is that you can plop your Lionchief engine down on your postwar layout and crank the power up and run it without having to worry about wiring in a new control system. I think Lionel sells several straight 18 volt DC power supplies for people who have no intention of running anything but Lionchief.

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