A snag in the third rail disrupted Metro services on the north-south route on Thursday afternoon.
The snag was spotted on the Dakshineswar-bound line between Noapara and Baranagar around 2.05pm, an official of the carrier said.
“As a result, third rail power has tripped. A power block was taken at 2.18pm to rectify it,” the official said.
The official said a Dakhsineswar-bound train was left stranded, on the elevated corrdior between the two stations, by the glitch.
The third rail provides electrical traction to trains. As the supply snapped, train services between Noapara and Dakshineswar had to be suspended.
“We ran a truncated service between Dum Dum and Kavi Subhash (New Garia),” said Kausik Mitra, the Metro spokesperson.
Services on the full stretch resumed at 7.11pm.
Both stations — Dum Dum was the terminal station until Noapara was included in the Metro map — have provisions for trains to switch tracks.
The disruption tormented thousands of passengers on the northern fringe of Kolkata.
Baranagar and Dakshineswar are the two stations after Noapara.
Dakhshineswar sees a footfall of over 20,000 people every day. Baranagar and Noapara see a lesser number.
Metro sources attributed the snag to the third rail current collector, which, located in the undercarriage of a train, draws power from the third rail.
It used to be a familar foe when it came to snags that Kolkata’s transport lifeline was infamous for. Burdened by an ageing fleet, snags were almost routine.
The older rakes have gradually been phased out after the new-age Medha rakes.
“The rake that was affected was not a new one,” said an official. “Access to the location of the snag was a challenge. Getting equipment to the spot and replacements took up some time. The stranded train will be removed after the snag is fixed,” he said.