Railroad Derailer

Overview

A railroad derailer is a mechanical safety device placed on track to forcibly derail any train that attempts to pass without authorization. A train rolling onto a derailer engages a hardened blade that strikes the wheel flange, lifting the wheel off the rail and bringing the train to a violent stop. Derailers are used to protect workers and prevent unauthorised movement of rolling stock.

How it works

A fixed derailer is bolted to the rail at the entrance to a siding or protected area. The Derailing Block and Blade sits between the two rails, with the derailing blade angled upward into the wheel path. Normally, the Operating Lever is positioned in an "out" or "safe" state, with the block swung or withdrawn clear of the wheels.

When the derailer is to be activated, the operator pulls or motorises the Operating Lever, which rotates about a pivot pin. The Linkage Rod Assembly couples the lever such that pulling drives the Derailing Block and Blade into the wheel path. A mechanical latch then engages, holding the block in place.

If a train attempts to enter at speed, the leading wheel contacts the blade. The blade angle causes the wheel to climb as the train's momentum drives it forward. The wheel lifts clear of the rail and the wheel and axle drop between the rails, a derailment.