Chenab Rail Bridge: The Tech Behind the World’s Highest Railway Bridge

Chenab Rail Bridge, the highest rail bridge and arch bridge in the world, is all set to be inaugurated by Prime Minister Narendra Modi on Friday. The inauguration ceremony is for the 63 km stretch of the Katra-Sangaldan section, part of the Udhampur-Srinagar-Baramulla Rail Link (USBRL), which also includes the Chenab bridge. Apart from that, the PM will also inaugurate the Anji Bridge, which is India's first cable-stayed rail bridge.

After the inauguration, Modi will also flag off the first Vande Bharat Train to travel on the world's highest arch bridge, making it fully operational. The bridge, which is also being called an engineering marvel, required the use of state-of-the-art machinery and human craftsmanship. To underpin the technology behind the project, we have listed the top five things to know about the Chenab Rail Bridge.

Chenab Rail Bridge: An Overview

The Chenab Rail Bridge is built over the Chenab River in the Reasi district of Jammu and Kashmir. Constructed using steel and concrete, it covers a distance of 1,315m across the river gorge. The length of the main arch is 467m (linear) and 550m (curvilinear). Under the executive agency of the Konkan Railway Corporation, the construction project was handled by Afcons Infrastructure. The bridge cost Rs. 1,486 crore to construct and has an expected lifespan of 120 years.

Hoisted 359m above the riverbed, the Chenab Rail Bridge supersedes the Daduhe River Railway Bridge in China as the world's highest rail bridge. As per Afcons, it is 35m taller than the Eiffel Tower. The project required the fabrication of 28,660 metric tonnes (MT) of steel. The structure is designed to handle trains travelling at the speed of 100kmph and wind speeds of 266kmph.

Tech Behind the Chenab Rail Bridge

• Coming to the design, the bridge uses a two-rib steel arch design with an open spandrel construction. Open-spandrel implies that the rail deck sits on vertical supports rising from the arch instead of being continuous. Weathering steel was used for the construction of the bridge, which is corrosion resistant and allows for temperature variation between -20 degrees Celsius to 45 degrees Celsius.
• Each segment of the bridge weighs 34 MT and was erected using the help of the world's tallest cable crane with a 127m high pylon, Afcons said. That is taller than the Qutub Minar.
• The Chenab Rail Bridge is designed to bear earthquake forces of the highest intensity zone-V in India. To ensure that the structure is secure, Phased Array Ultrasonic Testing machines were used to test the welds, a first in Indian Railways. Interestingly, the bridge required roughly 5,84,000km of welding to join different parts — about the same distance between Jammu Tawi and New Delhi.
• Throughout the bridge, structural health monitoring (SHM) systems have been placed. More than 100 sensors have been installed that monitor wind parameters, environmental conditions, structural responses such as vibration and load, and more. These sensors constantly send data to alert mechanisms.
• If any of the values are found to be beyond the safety parameters, it triggers a red signal to halt train operations and sounds alarms to alert station masters and control rooms. The health monitoring of the bridge is being handled by Tranz Rail Solutions along with Strainstall, part of the James Fisher group.