For the second day in a row, trouble was in store for lakhs of commuters taking the Dwarka-Noida City Centre/Vaishali corridor of the Delhi Metro, as signalling-related repair work along a major stretch of the Blue Line forced authorities to run trains on restricted speeds.
Apart from the current glitch, the 50-km-long corridor has been hit by three major snags this year — on March 29, May 13 and November 20 — which led to losses of eight or more trips.
How Metro ensures smooth travel, until system fails
The Delhi Metro’s signalling system is track-based: Sensors are fitted on the tracks along the entire DMRC network. When a train passes over the sensors, messages are passed to servers at certain stations. These are then forwarded to the Operations Control Centre and signals are accordingly relayed. All this happens on a real-time basis, enabling seamless movement of trains. When the system falters, drivers cannot push trains forward. They can run trains on restricted speed, only when the automatic mechanism is shut down.
Complaints started pouring in during peak morning hours as office goers boarded the trains, unaware that the system, which had completely come to a halt for around 30 minutes on December 5, had not returned to normalcy yet.
Trains were frequently losing contact with the Operations Control Centre (OCC) due to the glitch. The OCC, where train movements and related systems are continuously monitored on a giant screen, is akin to the Air Traffic Controller in airports.
According to Metro chief spokesman Anuj Dayal, repair work was completed between the Barakhamba Road and Dwarka Sector 21 stations on Wednesday night: “Around 17 engineers were deputed to reboot the system through the night. Work was mostly left in the stretch between Yamuna Bank and Vaishali.”
Accordingly, trains ran on two separate loops — between Dwarka Sector 21-Noida City Centre and Yamuna Bank-Vaishali. Due to this, those going towards Vaishali had no option but to board Noida-bound trains and change at Yamuna Bank to make their onward journeys.
“It is a software-related problem. Work is actually complete, but we are keeping the system under observation for some more time,” Dayal said. He added that the signalling system belongs to Siemens and log records of the glitches have been forwarded to the company’s headquarters in Germany for a detailed analysis.
Trains are running with a frequency of 3 minutes and 30 seconds on the Dwarka-Noida section, while the frequency on Yamuna Bank-Vaishali section is 5 minutes and 30 seconds.