The major milestone was achieved on Tuesday, informed the Northern Railway, which connected the two ends of the tunnel between Sumber and Arpinchala stations of Katra-Banihal section of Udhampur-Srinagar-Baramulla Rail Link (USBRL) project.
INDIA’S LONGEST TRANSPORTATION TUNNEL MADE THROUGH
Today a major milestone has been achieved by executing break-through of Tunnel T-49 between Sumber and Arpinchala Stations on on-going Katra-Banihal Section.
T-49 is 12.758 Km long tunnel and it is going to be longest tunnel of Indian Railway surpassing Peer Panjal Tunnel of 11.2 Km length constructed by USBRL on Banihal-Qazigund section.
- The south portal of the tunnel is located at an altitude of 1400 metres, while its north portal is located at an altitude of 1600 metres. The T-49 tunnel has been constructed using the New Austrian Tunneling Method (NATM), a modern technique of drill and blast method. The Northern Railway said that the cross section profile of the tunnel is modified horseshoe-shaped.
- The NATM is also known as the sequential excavation method (SEM). It uses the strength of the surrounding soil to the greatest extent possible to strengthen the tunnel structure. The NATM promotes constant monitoring. Being an SEM, the operation occurs sequentially to take most advantage of the ground conditions.
- T-49 tunnel has two tubes - one is the main tunnel and other being escape tunnel. As per international standards, the escape tunnel being constructed parallel to the main tunnel is connected by cross passages at an interval of 375m to facilitate rescue and restoration work. The tunnel has a ruling gradient 1 in 80 and designed speed of 100 kmph.
- The Northern Railway said that during construction activities, local population was employed by agencies for various works. Out of 272 km length of USBRL project, 161 kilometres has already been commissioned and operationalised. The work of the intervening stretch of 111 kilometre between Katra Banihal is under progress at rapid pace, the railways said. It added that several challenges were encountered in the course of construction such as shear zone, perched aquifer, and highly jointed rock mass, rock problems of squeezing and high ingress of water.
The south portal of Tunnel T-49 is located in picturesque Sumber Village at a distance of 45 km from District HQ Ramban at an altitude of 1400 meters, while North Portal of tunnel is located near Arpinchala village Tehsil Khari in Mahu-Mangat Valley at an altitude of 1600 meters. Several Challenges were encountered in the course of construction. The team of experienced engineers of N.Rly, M/s IRCON and the executing agencies M/s HCC & M/s AFCONS successfully negotiated all challenges and made possible to achieve this major breakthrough. During construction activities of the tunnel local population was employed by agencies for various works, in the region which has changed the overall socio-economic landscape.