THE TIME lag from the moment a derailment occurs to the moment the train stops can be crucial in minimising the damage which results, making it important to apply the emergency brake as soon as the wheels leaves the rail.
The Sicode inertial derailment detector provides a quick brake application in the event of a derailment, acting automatically without the driver needing to intervene. The manufacturer says it can be fitted to new or existing vehicles at low cost and with no risk of false activation, and is more efficient than past systems based on bogie-body distances which have discouraged widespread application through unrelaibility.
Sicode is linked to the brake pipe and cylinder pipe, and if a sudden vertical acceleration occurs, a pilot valve opens to exhaust the brake pipe to the atmosphere. A red trigger indicator is moved outwards for easy identification, and remains visible until reset. The Sicode-EP model is specifically designed for use on metro vehicles, opening micro-switches to trigger brake applications.