Nearly 1,800 commuters were stranded inside an eight-coach Metro for more than an hour, after the train stopped inside an underground tunnel between Central Secretariat and Udyog Bhawan stations on Tuesday.
When lights in the train went out and the air-conditioning stopped working, some passengers panicked. The restless passengers pushed open the emergency door of the train and stepped out on the tracks, thus halting the rescue mission.
Rescue delayed, commuters at risk
Delhi Metro officials tried to revive the train by rectifying the technical faulty. But it failed. Then the officials decided to rescue passengers with the help of another train. The rescue train was to push the stranded train and get it out of the tunnel.
Passengers in the train at Central Secretariat were asked to vacate and it was sent to push the stranded train to the nearest station. But the passengers of the stranded train were out on the tracks and the Metro offcials stopped the rescue train from proceeding towards the stranded train.
"We had to scrap the plan as some commuters, including women and children, forced open the emergency doors and came out on the tracks," said Anuj Dayal, chief spokesperson of Delhi Metro Rail Corporation (DMRC).
Fortunately, there was no loss of life. The Metro tracks have high voltage power lines running along and also the parallel tracks are close.
Why the train stopped?
For smooth movement of a Metro train, each coach is coupled with the other through a software communication system that guides the movement of the entire train. This software also issues commands to each coach, giving the relative position of the coach ahead.
On Tuesday, one communication coupler developed a snag, failing to communicate the message to the coaches.
The communication chain broke at fifth coach. This resulted in the automatic application of emergency brakes.
What the officials do?
Immediately after the halt, DMRC staff and operation control centre tried local troubleshooting repairs to re-start the train.
"There is a designated troubleshooting mechanism, which is referred to after the application of the emergency brakes by the Metro rail. Passengers' safety was not bypassed and the operations team was trying to detect the glitch. This is why it took nearly 90 minutes to re-start the train," an official was quoted in a section of media.
When troubleshooting did not work, DMRC decided to rescue passengers with the help of another train.
What happened during peak hour?
The Metro service on the Jahangirpuri to Huda City Centre line developed a software malfunction at 9.24 am. All passengers were evacuated by 10.45 am.
Passengers walked out of the tunnel and were brought to the Central Secretariat station. The stranded Metro began moving by 11 am. But due to bunching of trains, services remained affected for another hour.