When several parts of north Calcutta resembled rivers following the two-hour downpour, people rushed underground only to be let down by the Metro Railway.
A signal malfunction at Dum Dum station stalled Metro services for 30 minutes from 11.50am. The snag was fixed at 12.20pm — trains ran between Girish Park and New Garia till then — but the disruption continued for more than an hour.
“The trains could not shift to the New Garia (Kavi Subhash)-bound tracks in Dum Dum as the signal at the crossover point remained red. The signals at Belgachhia, Shyambazar and Sovabazar-Sutanuti stations, too, malfunctioned, resulting in suspension of service,” said a Metro spokesperson.
The rush-hour disruption inconvenienced thousands of commuters, many of whom tried to explore surface options but were stuck as the Dum Dum underpass and the adjoining roads were waterlogged.
“My daughter’s school gets over at 12.30pm. What would she do if I don’t reach there by then?” wondered Anima Sen, 28, whose daughter studies in Class I. She was frantically wading through knee-deep water in the Dum Dum underpass looking for a taxi after the Metro service was suspended.
The snag was repaired around 12.20pm, after which normal service was restored. However, thousands of commuters had gathered at Dum Dum and other stations by then. Commuters said the first few trains after the service resumed were packed beyond capacity.
“I was waiting at Belgachhia station from 12.05pm and when a train finally came around 12.30pm, I could not enter it. I finally managed to push myself into the third train,” said Priyanka Agarwal, a resident of Lake Town.
Explaining Tuesday’s snag, a Metro engineer said the crossover point between the two sets of tracks remains locked till the signal there remains red. “A train terminating at Dum Dum station travels about 200 metres towards Noapara before crossing over to the Kavi Subhash-bound tracks,” said the engineer.
Point signalling system — locking or unlocking of the crossover point linked to the signal at the spot — is part of the safety interlocking system Metro had introduced when it switched over from the block or manual) signalling system to the automatic mode last year.
In the block system, the signals were at a distance of one to two kilometres from each other. After a train leaves Dum Dum for New Garia, the next train could not start before the first had travelled 180 metres beyond the third station, Shyambazar. As soon as a train crossed the 180-metre mark, a message would automatically be sent to the panel operator, who would allow the second train to leave.
In the new system, multiple signals have been installed between the stations to facilitate faster service. As soon as a train goes past a signal, the previous signal automatically turns green, allowing the next train to move. Besides, if a snag develops in any one section, all the signals in that section turn red as a safety measure.
At Rabindra Sadan station, a man’s hand got stuck between the doors of a train which he had boarded in a hurry while the gates were closing. Arup Basak, 40, started screaming when a passenger pressed the emergency alarm. “The train was brought back to the platform and the gates were reopened. The man was given first aid,” said an official.