A power failure knocked out PATCO service Tuesday at every station in Philadelphia except one at Eighth and Market Streets, an interruption that lasted until shortly after 4 p.m.

Eastbound service from 15th/16th and Locust Station resumed at 4:12 p.m., said John Hanson, the chief executive of the DRPA.

PATCO relies on electricity routed through SEPTA's Sansom Street substation for power at its three stops along Locust Street, Hanson said, and that power source was disrupted. A SEPTA maintenance crew was at the substation at Eighth and Sansom Streets investigating indications of problems with an electrical circuit on the line, SEPTA spokesman Andrew Busch said, a relatively routine problem. While troubleshooting, the crew unintentionally cut the line providing power to the PATCO stations, he said.

The outage does not appear to have hurt SEPTA service, he said.

PATCO trains are powered through a third rail in the tracks, but the severed SEPTA line provides electricity to the stations and to the train control system that ensures vehicles maintain safe speeds.

An average of 37,844 riders used PATCO each week day in 2017, according to the transit agency.