Thousands in Santiago were stranded during an evening commute as a power outage shut down the busy Metro line during rush hour.

Cell phone video illustrates the growing anxiety of passengers trapped in the train...as they pounded on the doors, desperate for metro staff to open them.

And there was little ventilation inside as cramped riders waited nearly 40 minutes before metro staff came to their rescue.

"There was much despair and heat inside and they didn't want to open the doors. That was the problem," a passenger said.

Among those trapped were disabled people, pregnant women and children.

The state-owned metro has yet to make an official statement about what caused the electrical outage.