A Delhi Metro Rail Corporation (DMRC) official said that the 'track circuit' on Blue Line (Line 3), that connects Dwarka to Vaishali, dropped while a train developed snag on Violet Line (Line 6) around the same time.
"Trains were running at a restricted speed on Line 3 (due to track circuit failure) and lane 6 (train motoring issue) leading to bunching. Services became normal as the bunching was cleared.
This had a cascading effect as trains frequently stopped on tracks before entering stations while crowd kept swelling on the platforms.
Line 6 connects Faridabad's Escorts Mujesar to ITO in the heart of the capital.