Building an Indian Railways network that reaches and connects the seven sister states of North-East has always been acknowledged as a daunting and challenging task. But, to be able to build the world’s tallest girder railway bridge in the Himalayan ranges, is truly a remarkable feat. Come 2019, this dream project of Indian Railways will turn into a reality. Called Bridge No 164, the world’s tallest girder railway bridge, will have a pier height of 141 metres. That’s almost twice as high as Qutab Minar! At present, Europe’s Mala-Rijeka viaduct is the world’s highest at 139 metres. The tallest girder bridge is part of the upcoming 111-kilometres long Jiribam-Tupul-Imphal railway line. The ambitious railway line upto Tupul is expected to be complete by 2020, while the tallest girder railway bridge will be ready by June 2019, says Saibaba, Chief Engineer Construction, Northeast Frontier Railway (NFR). In an interaction with Financial Express Online, he said that the best international practises are being used for the construction of the crucial bridge. We take a look at some interesting details about the world’s tallest rail girder bridge and the Jiribam–Tupul–Imphal railway line:
1. Bridge No.164 is being built across the valley of river Ijai near Noney and has been designed to take a maximum train speed of 120 kmph.
2. The bridge will also help in crucial freight movement. According to Indian Railways, the bridge is designed to carry up to 25 ton axle-load freight trains as well.
3. The Jiribam–Tupul–Imphal railway line cuts across the lower Himalayan ranges necessitating series of tunnels through the hills and tall bridges across the deep valleys. The line will connect Manipur’s state capital Imphal to Jiribam which is on the western-most boundary of the state. Jiribam is an area that adjoins the Cachar district of Assam. As of now Manipur’s capital Imphal has no railway connectivity.
4. Area prone to earthquakes: Brige No. 164 is located in Seismic Zone-V, making it highly vunerable to earthquakes. According to project in-charge Saibaba, a “site-specific design spectrum had been developed to ensure long-term stability of the bridge.” State-of-the-art techniques will be used to also check landslides due to heavy rains or earthquakes. All these techniques are being used for the first time in the North-East.
5. Wind speed: Studies have been conducted to analyse the stability and safety of the bridge under the maximum design wind speed of 241 kmph and the bridge is being built accordingly. Also, the entire Northeast area receives very heavy rainfall for almost 6 months in a year. According to Indian Railways officials that FE Online spoke to, the general soil profile is shale which is “most undesirable” for bridges of this magnitude. Hence the biggest challenge in building the bridge is to ensure sustainability against the extremities of nature.
6. The final cost of the bridge is assessed to be around Rs 400 crore including the safety work. The cost of the complete project upto Imphal is expected to be around Rs 13,800 crore.
7. Protection against terrorist attacks: The railway line and the bridge are being built despite several threats from militant outfits operating in the area. This bridge will be provided 24×7 security cover with personnel posted exclusively at the site. Additionally, surveillance of the bridge through CCTVs and remote monitoring by instruments and sensors is also being considered to ensure the safety. According to Indian Railways, at the conceptual stage an advisory group concluded that public assets are unlikely to be a target for militant outfits. Hence unlike the upcoming Chenab bridge, this one will not be blast-proof.
8. A dedicated laboratory with equipment and manpower has been set up by Indian Railways has at the bridge site to test and pass all the material that goes into the making of the bridge. Expertise of outside institutes is also being taken for double-checking of the quality control systems. The health and in-service performance of the bridge is proposed to be monitored by using sensors fixed to the bridge at critical locations. The sensors also record climatic features like wind speed.
9. Expertise: Three IITs (Kanpur, Roorkee and Guwahati) and NIT/ Silchar are also associated with this ambitious Indian Railways project by way of technical support and proof-checking of designs to make the bridge cost-efficient and sustainable.
10. At 10.54 kilometres, the Jiribam-Tupul-Imphal railway link will also boast of one of the longest railway tunnels on the Indian Railways network. In a first, the longest tunnel in the North-East will also have a service tunnel alongside with connection to the main tunnel at intermittent points. This will help in both maintenancew work and situations of emergency. According to Indian Railways officials, all tunnels on the railway link are in advanced stages of completion. For tunneling work, state-of-the-art NATM (New Austrian Tunneling Method) is being used.