What is a Magnetic Track Brake?

A Magnetic Track Brake is an emergency braking device on trains. It uses powerful electromagnets to clamp brake shoes directly onto the rails, creating friction independent of the train's wheels.

When is the Magnetic Track Brake used?

It is typically used only during emergency braking when the train needs to stop in the shortest distance possible, or when rail adhesion is low (e.g., wet leaves or ice) making wheel brakes less effective.

Does the Magnetic Track Brake touch the rail?

Yes, unlike Eddy Current brakes, the Magnetic Track Brake physically contacts the rail head to generate friction. This physical contact can cause wear on both the brake shoes and the track if used frequently.

The Emergency Anchor: Magnetic Track Brakes Explained

When friction isn’t enough. Learn how Magnetic Track Brakes clamp directly onto the rail to provide critical emergency stopping power independent of wheel adhesion.

December 10, 2025 12:09 pm

A Magnetic Track Brake (often abbreviated as Mg brake) is a supplementary braking device used on trains and trams. Unlike standard disc or tread brakes which apply force to the wheels, the magnetic track brake bypasses the wheels entirely. It consists of a pair of electromagnets suspended between the wheels of a bogie, which are lowered onto the rail head to generate friction directly against the track.

Why Do We Need It?

Standard railway braking is limited by the “adhesion” (grip) between the steel wheel and the steel rail. If a train brakes too hard using only wheel brakes, the wheels will lock up and slide (skid), extending the stopping distance. The Magnetic Track Brake solves this by interacting directly with the rail. It is primarily used for Emergency Braking to achieve the shortest possible stopping distance, regardless of whether the rails are wet, icy, or slippery.

How It Works

The system operates on simple electromagnetic principles:

Suspension: In normal operation, the brake shoes are held up, clear of the rails, by springs or pneumatic cylinders.
Activation: When the emergency brake is triggered, a strong electrical current is sent to the electromagnets.
Clamping: The magnetic attraction pulls the brake shoes down firmly onto the steel rail head.
Friction: The physical friction between the brake shoe lining and the rail creates a massive dragging force, slowing the train down rapidly.

Comparison: Wheel Brakes vs. Magnetic Track Brakes

The Mg brake is rarely used for service braking (normal stops) because it causes wear on the rails and is jerky for passengers. It is a safety overlay.

Feature	Standard Wheel Brake (Disc/Tread)	Magnetic Track Brake (Mg)
Force Application	Applied to the Wheel/Axle	Applied directly to the Rail
Adhesion Limit	Limited by Wheel-Rail grip (Wheel slide risk)	Independent of Wheel adhesion
Usage	Service stops & Speed control	Emergency situations only
Power Source	Compressed Air	Electricity (Battery/Catenary)
Contact Type	Friction	Friction (Metal on Metal)