📹 This article is based on the Skyline Ziplines video explaining the science behind the M24 trolley’s eddy current braking system.

What Is Eddy Current Braking in Zipline Systems?

Eddy current braking in zipline systems is a frictionless method of controlling rider speed using magnets, metal, and motion—without any physical contact between braking components.

At first glance, it may seem like magic. There’s no rubbing, no squeezing, and no mechanical brake pads. Yet the trolley still slows riders smoothly and safely. To understand how this works, we need to take a closer look at the physics behind it.

Why Traditional Braking Doesn’t Apply Here

Think about riding a bike downhill.
To slow down, you squeeze the brakes, creating friction between brake pads and the wheel or disc. That friction generates heat, wear, and eventually requires maintenance.

The M24 trolley works differently.
Nothing touches. Nothing rubs. And yet the trolley can still reduce speed effectively.

So how does it do that?

Meet the Magnetic Braking System

Inside the wheels of the M24 trolley are strong rare-earth magnets. These magnets sit extremely close to the aluminum sidewalls of the trolley—without actually touching them.

Even with a small air gap and no physical contact, the system can still slow the rider. The secret lies in a phenomenon known as eddy currents.

What Are Eddy Currents?

To understand eddy currents, imagine dragging your hand through water.
The water pushes back against your hand, creating smooth, controlled resistance.

Eddy current braking works in a similar way—but instead of water, it uses an invisible electromagnetic force.

As the magnets spin past the aluminum side plates, they generate swirling loops of electrical current inside the metal. These swirling loops are called eddy currents, similar to tiny electrical whirlpools.

Just like water pushing against your hand, these electrical whirlpools push back against the moving wheel, creating resistance.

Why Eddy Current Braking Is So Smooth and Safe

Here’s the most important part:

• The faster the trolley moves, the stronger the eddy currents become
• Stronger eddy currents create more braking force
• As the trolley slows down, the currents weaken naturally

This means:

• no sudden or jerky stops
• no friction
• no wear on braking components
• consistent performance over time

It’s essentially a self-regulating brake that automatically adjusts to speed.

A Simple Example of Eddy Current Braking

You can demonstrate eddy current braking with a simple experiment.

Drop an aluminum plug through an aluminum tube, and it falls freely under gravity.
Now drop a magnet through the same tube.

Instead of falling quickly, the magnet slows dramatically—almost as if it’s falling through honey. That resistance is caused entirely by eddy currents forming inside the aluminum.

The same principle is at work inside the M24 trolley.

Eddy Current Braking and Zipline Safety

Eddy current braking plays a critical role in making modern zipline systems both thrilling and safe.

Because the system:

• has no physical wear components,
• produces consistent braking,
• and automatically responds to speed,

it significantly reduces maintenance demands while improving ride quality and predictability.

For clients using turbine-style trolleys, Skyline Ziplines also offers similar magnetic braking wheels at a smaller scale, applying the same proven principles.