What is a Lionel E-unit?

You don’t have to hang out with Lionel enthusiasts for long before you hear about a mysterious thing called an e-unit. But what is a Lionel e-unit, anyway?

The Lionel e-unit is an electromechanical device that allows Lionel trains to sequence through forward, neutral, and reverse when the operator cycles power to the track, making it easier to simulate train operations. Originally the e-unit operated using a solenoid, copper fingers and a drum to change the motor’s polarity. In recent years, various companies have replicated the e-unit’s function with electronics.

What the Lionel e-unit does

Lionel e-unit
It may not look like much, but the Lionel e-unit was a big deal when its predecessor company, Ives, invented it in 1924.

The Lionel E-unit has one job. It cycles the direction when you cut power to the train and restore it. It cycles between forward, neutral, reverse, neutral, and back. Most Lionel transformers have a button to interrupt power to make the direction change more convenient.

Adding the neutral gear was the innovation. Simple electrical devices to change the direction when interrupting power already existed. But throwing an engine into reverse at high speed causes problems, generally speaking.

How the e-unit works is straightforward, but it was a big deal when Lionel rival Ives invented the device. Lionel couldn’t make something comparable without violating Ives’ patent, and they didn’t want to wait 17 years for the patent to expire, so Lionel and rival American Flyer teamed up to buy Ives in 1928.

The e-unit is also the reason Lionel trains with conventional, traditional open frame motors have their distinctive buzz. The buzz is the solenoid operating on AC power rapidly cycling 60 times per second.

Although generally reliable when new, the e-unit can develop problems over time due to arcing and heat. Eventually the heat deforms the contacts, and eventually the motor stops running. Any Lionel repair shop knows how to repair them. It’s probably the most common repair on vintage Lionel trains. I generally swap them out and leave repairs to someone more qualified. Here’s how to wire another one in. And, in a pinch, here’s how to wire a train to run without one, if you can live with running forward only.

Electronic e-units

Today, it’s possible to replicate the electromechanical function with electronics. Modern-era Lionel trains generally use electronic e-units with modern can motors. It’s a cheaper solution and generally maintenance free. It’s also quieter, which is either a good thing or a bad thing, depending on whether you had the trains when growing up or not. Higher-amperage electronic e-units are also available for the older open frame motors.

I use and recommend the JVDE electronic e-unit for older trains. It works extremely well, just be aware it doesn’t necessarily fit in the smaller O27 steam engines. It’s fine in the larger O gauge steam engines and in diesel engines.

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One thought on “What is a Lionel E-unit?

  • September 1, 2022 at 4:32 pm

    I have heard that some people solder a diode into one of the wires leading to the solenoid coil so it will be operating on DC power and the buzz is replaced by a single, faint click. The locomotive continues to operate on AC.

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