Ramban: The 12.895 km escape tunnel of the 12.75 km longest tunnel of the Indian Railways T-49 between Khari and Banihal stations of Katra-Banihal section of the Udhampur-Srinagar-Baramulla Rail Link (USBRL) project was successfully made through after negotiating a major cavity formation on Thursday.
The breakthrough was achieved in presence of Chief Administrative Officer of USBRL, S P Mahi along with his team of officers and officials. As per the statement issued by USBRL, a major milestone has been achieved by executing the breakthrough of Escape Tunnel T-49 between Sumber and Khari stations on the Katra-Banihal section of the USBRL project.
This is the longest escape tunnel of India and the line and level of the tunnel are precisely achieved during the breakthrough of the escape tunnel.
It is a modified horseshoe-shaped tunnel connecting the summer station yard on the south side and Tunnel T-50 after crossing Bridge No 4 over Khoda Nallah on the north side at Khoda village.
The elevation of the south end at Sumber is approximately 1400.5 m and of the north end is 1558.84 m.
The ruling gradient inside the tunnel is 1 in 80.
The boring was done from various faces from South portal, north portal and through three Adits that in Urnihal (323 m), Hingni Adit (280 m), and Kundan, Adit (739 m).
The Tunnel T-49 is a twin tube tunnel comprising the main tunnel (12.75 km) and escape Tunnel (12.895 km) connected with 33 cross-passages at every cross passage.
The main tunnel mining was already completed and final lining works are progressing at a rapid pace.
The tunnel has been constructed by the New Austrian Tunneling Method (NATM), which is a modern technique of drill and blast processes.
The tunnel is constructed as per the international standards, in which the provision of an escape tunnel has been made to facilitate rescue and restoration works in emergency cases.
The escape tunnel passes through the Ramban formation of the Young Himalayas and various tributaries and rivulets of River Chenab like Khoda, Hingni, Kundan and crosses all along the alignment, making mining more of a highly challenging task.
During the construction activities of the tunnel, more than 75 percent of workers from nearby villages were engaged in various construction activities, thereby ushering a positive change in the overall socio-economic landscape of the region.
Of the total 272 km length of the USBRL project, 161 km has already been commissioned and operational while the work of balance 111 km, the intervening stretch between Katra-Banihal is under progress at a rapid pace.
The Katra-Banihal section traverses through the hilly terrain of the lower Himalayas in which weak geology, remoteness, inaccessibility of the area, weather conditions, landslides, and shooting stones on access roads are major challenges.
It has several major bridges and very long tunnels, which are under construction at different stages.
The T-49 tunnel (12.75 km) from Sumber to Seeran village in Khari tehsil of Ramban district is the longest transportation tunnel in the country.
There are three other tunnels on this project, the lengths for which are close to that of tunnel T-49.
For 10.20 km tunnel T-48 between Dharam and Sumber station breakthrough has already been achieved.
The other two tunnels are 11.25 km T-15 between Sangaldan and Basindhadar stations and 11.2 km Pir Panjal Tunnel between Banihal and Qazigund stations.