Prime Minister Narendra Modi will inaugurate the 4.94-km-long rail-cum-road Bogibeel Bridge, the longest such in India, on Tuesday. The bridge, which was a part of the Assam Accord and sanctioned in 1997-98, is likely to play a crucial role in defence movement along the India-China border in Arunachal Pradesh.

The foundation stone of the project was laid by former prime minister H D Deve Gouda on January 22, 1997, while work commenced on April 21, 2002 under the Atal Bihari Vajpayee-led government. December 25 happens to be Vajpayee's birth anniversary.

Because of the inordinate delay in implementation, the cost of the project escalated by 85 per cent to Rs 5,960 crore from the sanctioned estimated cost of Rs 3,230.02 crore. The total length of the bridge was also revised to 4.94 km from the earlier 4.31 km.

Realising its strategic importance, the central government had declared the construction of the bridge as a National Project in 2007, thereby assuring availability of fund for speedy construction.

Although it will ease out inconvenience caused to people living on the northern side of Brahmaputra to a great extent, officials said the defence requirement played an important role while sanctioning the structure and its design.

"The bridge will enhance the national security of the eastern region by facilitating swift movement of defence forces and their equipment. It was constructed in such a way that even a fighter jet can land on it in case of emergency," a defence source said.

Moreover, because of the technology used, the Air Force will have three landing strips, he said.

"The biggest advantage of the bridge will be easy movement of troops from southern to northern bank. This means travelling to the farthest most point of India's border with China will be shortened by several hundred kilometres.

"First, the Dhola-Sadiya bridge and now Bogibeel -- these two are going to enhance India's defence prowess," a senior Army official said.

Northeast Frontier Railway (NFR) Chief Public Relations Officer Pranav Jyoti Sharma said almost 75 per cent of the 4,000-km long border that India shares with China is in Arunachal Pradesh, and the bridge will help in logistical support for the Indian Army manning the border.

The Bogibeel Bridge over river Brahmaputra is situated 17 km downstream of Dibrugarh city in Assam, and it has been constructed for double-line broad gauge track along with three-lane roads, he said.

"This bridge will be the lifeline of the north eastern part of the country and will facilitate connectivity between north and south banks of river Brahmaputra in the eastern region of Assam and Arunachal Pradesh.

"The remote districts of Anjaw, Changlang, Lohit, Lower Dibang Valley, Dibang Valley and Tirap of Arunachal Pradesh will be greatly benefited," Sharma said.

The road distance from Dibrugarh to Itanagar will be reduced by 150 km and the railway travel distance between these two points will shorten by 705 km, while this bridge will provide an alternate and shorter route from Dibrugarh through north bank of Brahmaputra to Delhi and Kolkata via Rangiya, he added.

"The distance from Dibrugarh to Rangiya will be reduced by 170 km... Upper Assam and Eastern Arunachal Pradesh will see massive socio economic development," the CPRO said.

Lakhimpur and Dhemaji in Assam will also benefit from the bridge, as the two districts do not have any reputed educational institute or good medical service.

Students and patients have to cross the river on boat to come to Dibrugarh, which houses the famed Dibrugarh University and Assam Medical College, besides a dozen other such centres.

Sharma informed that 30 lakh bags of cement, 19,250 mt reinforcement steel and 2,800 mt structural steel were used for construction of the mammoth structure.

For the super structure of the main bridge, 77,000 mt of steel fabrication was required, he said.

Meanwhile, the All Assam Ahom Sabha (AAAS), an organisation that has been demanding the new rail-cum-road bridge at Bogibeel to be named after the Ahom Kingdom's founder, on Monday welcomed Prime Minister Narendra Modi's visit to inaugurate the bridge on Tuesday.

Modi will inaugurate the 4.94-km-long rail-cum-road bridge, the longest such in India, at Bogibeel on Tuesday.

"The Ahom Sabha acknowledges with deep appreciation the diligence with which the Prime Minister expedited the completion of the bridge," the Dibrugarh district unit of the organisation said in a statement.

"The Ahom Sabha feels that the inauguration of the bridge would mark an epoch in the history of the region and would contribute to the realisation of the national ideals of a composite humane society of Assam as well as India," it stated.

"In fact, these are also the ideals of the Ahom Sabha, an organisation that has above all tenaciously striven for building bridges across peoples and cultures."

The AAAS has been demanding the new bridge over the Brahmaputra to be named after the founder of the erstwhile Ahom Kingdom Chaolung Siu-ka-pha.

Meanwhile, a group of boatmen making their living ferrying people and goods across the Brahmaputra see Bogibeel as a loss of livelihood.

Over 40 boats operate from the north and south banks of the Brahmaputra river, ferrying not just people but also two-wheelers and cars. Of these, two are operated by the state government, while the rest are privately owned.

Each boat requires three people to operate.

The boatmen, those running food stalls and the vehicle operators carrying people to and from the ferry ghats fear that from then on they will have to look for an alternative source of livelihood.

"In a joint family of 12 members, I and my brother operate one boat from Bogibeel ghat. After paying Rs 75,000 rent for the boat per annum and spending on the salaries of the boatmen, we earn around Rs 30,000 per month," a private ferry operator at Bogibeel ghat said.

It takes 45 minutes to two hours to cross the river on the boats. But once the bridge is open, it will take just 10 minutes, saving not just time, but also money.

While the government-operated boats charge Rs 18 per person, Rs 800 for small cars and Rs 1,000 for SUVs, the privately-operated boats charge way more for ferrying people and vehicles between Bogibeel ghat and Kareng Ghat in Dhemaji district, an official of the state Inland Water Transport Department said.

According to the official, some of the boats will be shifted to other ghats. But the private boat operators fear that they won't be able to get a similar opportunity and even if they do, it won't be financially viable.