PHOENIX -- Power was down across the entire Valley Metro light rail line Thursday afternoon.
Metro light rail officials tweeted a service alert at about 1:15 p.m.
A power-receiving station that feeds the region, including SRP and APS, experienced a capacitor bank failure, causing a ripple effect and subsequent power imbalance, according to Hillary Foose with Valley Metro.
When the imbalance occurred, the AC main breaker tripped open and the traction power substations shut down.
Crews manually reset the breakers on all 15 substations spread out across the light rail line. Power to overhead lines was restored gradually as the substations became active.
Trains were moving again at approximately 2:10 p.m.
"This is a highly unusual occurrence; however, our system did what it is designed to do in protection of itself and the public," Foose said.
Service alert cont.: Trains are moving again with minimal power. Pls bear with us as we get back up and running.— METRO light rail (@METROrail) October 24, 2013
Service alert: Power is down across entire light rail line. Trains are without power. Please stay tuned for details. Delays are assumed.— METRO light rail (@METROrail) October 24, 2013