Bridging the gap
The Delhi Metro Rail Corporation (DMRC) for the first time will run its trains for public on an under construction bridge after conducting trial run on it for about seven to 10 days. HT reports.Updated: Sep 09, 2010 23:29 IST
The Delhi Metro Rail Corporation (DMRC) for the first time will run its trains for public on an under construction bridge after conducting trial run on it for about seven to 10 days.
Due to time constraints trial run for three to four weeks will not be possible on the bridge that Gammon India — which is allegedly responsible for metro crane mishap at Zamrudpur — built over the Indian Railways tracks at Okhla on the Central Secretariat-Badarpur corridor.
According to Kumar Keshav, director (projects), DMRC: "The basic construction of the bridge is almost completed and our men will install overhead electrification (OHE) system, signal system and track within seven to eight days. We are expecting to extend trial run from Lajpat Nagar to Okhla within a week's time and further extend it till Sarita Vihar within 10 to 15 days. We have to complete the trial run on the entire stretch till Badarpur at the earliest as we have to make the corridor operational by end of this month."
This is the longest span ever built by the DMRC. Earlier, the Delhi Metro had constructed a bridge over the Indian Railways lines near Pragati Maidan, where the length of the main span was 93 metres.
The DMRC had to use such a long span over the Northern Railways track as four Indian Railways lines are passing below the bridge. The existing railway tracks below this bridge link New Delhi with Agra, Mathura on the Mumbai main line and then to other parts of the country. Therefore, it is a very important railway stretch of the Indian Railways network.
The bridge, which is located between the Okhla and Jasola Metro stations, has a total length of 250 metres and is divided into three spans. While the middle span is of 100 metres, the other two spans on the sides are of 75 metres each.
The Delhi Metro has employed the 'Balanced Cantilever Construction methodology (BCLC) for its construction so that the rail traffic below the Metro corridor is not hampered. This technique employs the use of a bridge builder that constructs the bridge segment by segment at a time.
"The construction of this bridge was difficult since the bridge was built on a very sharp curve with a 300 metre radius and the installation of the individual segments of the bridge on the curve was difficult as the rail traffic moving below could not be obstructed during the construction," said Anuj Dayal, DMRC spokesperson.