Completes tunnel below railway lines in just three days Tunnel constructed 12 metres below the railway line Work done without affecting the movement of trains NEW DELHI: The Delhi Metro Rail Corporation has achieved another major engineering feat by successfully completing construction of one of the two tunnels below the Indian Railways' line at Safdarjung in just three days. According to DMRC officials, the work was carried out without affecting the movement of trains. The tunnel was constructed 12 metres below the railway line to ensure that the tracks were not affected. Trains ply frequently on that route. "A dedicated team of DMRC engineers and surveyors rigorously monitored the process round-the-clock to ensure that the movement of trains was not affected. General monitoring of the tracks was done for seven days before undertaking the tunnelling work earlier this month,' said Anuj Dayal, Chief Public Relations Officer of DMRC. The DMRC had sought permission from the Commissioner of Railway Safety before execution of the project. "A detailed schedule of the movement of trains on the route was also taken from the railway authorities,' Mr. Dayal said. A German-made tunnel boring machine, known as the "Earth Pressure Balancing Machine', was used for the project. The engineers used an equipment called the "Digital Autolevels' to monitor the tunnelling process. The equipment automatically records accurate settlement levels. "The settlement recorded for the entire stretch was about 8 mm to 9 mm, which is well within the prescribed accessible international limits of 20 mm,' he added. In Phase I, Delhi Metro had earlier constructed its lines below the Indian Railways system in New Delhi and Delhi Main stations,' Mr. Dayal said. The second parallel Metro tunnel to be constructed on this route between Central Secretariat and Gurgaon is expected to come up in another month's time which will pass below the Safdarjung airport area.