Two Faults Lead to Railway Tunnel Ventilation System Damage

Location: Rogers Pass

Regulated industry sector: Electrical - High voltage electrical system (greater than 1000V)

Incident overview

A high voltage power supply and backup generator for a railway tunnel ventilation system were damaged due to a fault in an underground junction. An electrical fault in the junction box caused the ventilation system to lose power, affecting one tunnel and cutting off power to both ventilation systems. The backup generator detected the power loss and started to re-energize the fans. A second fault occurred, and the resulting voltage spike damaged the junction box. This caused the power to be cut off again and damaged the generator's electronic voltage regulator (EVR).