The Safety Valve: Understanding the Railway Headshunt

What is a Headshunt?

A Headshunt (also known as a “Shunting Neck” or “Drill Track” in North America) is a short length of track, typically a dead-end, that connects to a siding or a marshalling yard. Its primary purpose is to allow locomotives to perform shunting maneuvers—such as moving wagons between tracks or reversing direction—without entering or blocking the active Main Line.

The “Run-Round” Maneuver

The headshunt is an essential component of the “Run-Round” loop. When a train arrives at a terminal station or a dead-end siding, the locomotive is trapped at the front. By uncoupling and moving into the headshunt, the locomotive can reverse onto a parallel track, bypass the wagons, and re-couple at the other end to pull the train in the opposite direction.

Safety and Protection

Because shunting involves frequent back-and-forth movements, there is a risk of a train overshooting its limit. To protect the high-speed main line from these movements, headshunts are often equipped with:

• Buffer Stops: A physical barrier at the end of the track to stop the train.
• Trap Points (Catch Points): Derailing mechanisms placed between the headshunt and the main line to deliberately derail a vehicle if it passes a signal at danger, preventing a collision with a passing passenger train.

Comparison: Headshunt vs. Siding

While they look similar on a map, their operational functions are distinct.

Why is it Critical for Capacity?

Without a headshunt, every time a freight train needs to sort wagons in a yard, it would have to pull out onto the main line to switch tracks. This would force all high-speed passenger trains to stop, creating massive delays. The headshunt isolates these slow, complex movements, ensuring the main network flows smoothly.