USA: An earthquake early warning system that uses Positive Train Control to apply train brakes automatically is being tested by Los Angeles commuter operator Metrolink, California Department of Transportation and the US Geological Survey.

Metrolink’s current early warning equipment uses the US Geological Survey’s ShakeAlert system, which provides alerts when an earthquake has begun and protective action should be taken. It currently triggers automated messages telling train crews to slow or stop, but does not include automated brake enforcement.

The latest development sends PTC messages to trains in the impacted area based on the severity of the earthquake, automatically stopping or slowing trains as necessary. It also provides enhanced data to support infrastructure inspection and the resumption of services.

The technology is being piloted on the 91/Perris Valley Line between Riverside and Perris, ahead of a potential expansion across the entire Metrolink network.