February 13, 2017 TnH Global

Railways to use hi-tech survey for high-speed train corridor

The railways will use LiDAR technology — which involves conducting an aerial survey, and is known to give accurate data on the contours of land, even below vegetation — to expedite work on India’s first high-speed train corridor between Mumbai and Ahmedabad.

The use of Light Detection and Ranging, or LiDAR, will allow the survey of the 508km corridor to be completed in 9-10 weeks against the normal 6-8 months. It will help the national transporter start ground work on the Modi government’s dream project by 2018. According to the plan, almost the entire corridor will be on an elevated track, except 21km that will be underground. Of the 21km, 7km will be undersea.

The survey will be conducted by a helicopter, which carries equipment, including a high-resolution digital camera (100 megapixel), a laser scanner and a data recorder. An official said LiDAR was a remote-sensing technology that measured distance by illuminating a target with a laser and analysing the reflected light. The GPS unit interacts with GPS satellites to finalise the ground control points.

“The total flying time for covering the full corridor will be 30 hours. The preparatory work and time taken in processing of data is quite high, but still the process allows the survey of the full 508km in 9-10 weeks instead of 6-8 months,” Mukul Mathur, executive director (PPP), railway board, said. The exercise is highly accurate and enables capturing data of buildings and forest,” Mathur said, adding that this technology would be used for the survey of a rail line for the first time. For the survey, the helicopter will fly at a height of 500 metres while identifying 15.6 points per square metre.

As the survey generates very accurate data, the permission of the defence ministry and the DGCA will be sought, an official said.

The LiDAR survey is among four surveys —geo-technical investigation, hydrological survey and land plan preparations — being conducted by RITES at a cost of Rs 40 crore to finalise the alignment of the corridor. Nearly 81% of the funding for the project, estimated to cost Rs 97,636 crore, will come by way of a loan from Japan.

News Source: timesofindia.indiatimes.com