The glitch was reported around 7.50 pm in the stretch between Vishwavidyalaya and Jahangirpuri stations, a metro official said.
The distance between Rajiv Chowk and GTB Nagar stations, which usually takes around 20 minutes to cover, took around one hour today, a commuter said.
Due to the snag, both Samaypur Badli and Gurgaon-bound trains ran on a single track between the affected stretch, leading to delays along the entire corridor, the official said.
"Necessary overhead wire equipment repair work is being undertaken and normalcy on this section is likely to be restored shortly," the official added.