Bridging the Mighty Indus

On the way to Peshawar along the Grand Trunk Road if you take a left after crossing the concrete bridge over the River Indus at Begum ki Sarai, 2 km onwards you will rewarded by a magnificent view of a 460-metre-long steel road/rail bridge that is supported on three massive masonry and stone pillars. The Attock Bridge, as it is known, is just one – and perhaps the most impressive of five bridges that the British constructed over the Indus in less than 50 years.

The development of a railway network in northwestern colonial India began in 1855 with three lines, the Scinde, Punjab and Delhi Railways. Unlike the tracks extending from Bombay and Calcutta which had commercial worth, the ones in the northwest were for strategic purposes. Over the next 25 years, the network spread up from Karachi towards Sukkur and northwest from Delhi towards Lahore and the logistics base of the British Indian Army at Rawalpindi. It also extended down from Lahore towards Multan and Bahawalpur. By 1878, the railways had bridged the five rivers of the Punjab: the bridge over the Beas (1869), the bridge over the Ravi at Jassar and Lahore, the Alexandra Bridge over the Chenab at Gujrat (1875), the mile long bridge over the Jhelum (1876), the bridges over the Sutlej at Phillaur (1870) and the Empress Bridge at Bahawalpur (1878).

However, the formidable barrier of the River Indus now lay ahead. With their earlier experience, engineers were aware that bridging rivers at open sites where the course was not confined between rocky hills was more difficult. Therefore the early road/rail bridges across the Indus were constructed at Attock, Sukkur and Khushalgarh – where the river was confined.

From the time that the East India Company annexed the Punjab in 1849, replacing the bridge of boats on the Indus at Attock with a permanent solution was under serious consideration and in 1860 work commenced on building a 7.3 metre wide and 2.5 km long tunnel. However due to leakages, machinery breakdowns and cost overruns, the project was abandoned when only 78 meters remained between the two ends of the boring. The Second Afghan War gave an impetus to extending the railway line up to Peshawar and by 1879, the line from Rawalpindi had arrived at Attock on the southern side of the Indus. A year later, it had also been laid from the other bank onwards till Peshawar. But the construction of the bridge remained.

When the Indus arrives at the Attock Gorge, it has already traversed 1,500 km draining an area of 310,800 sq km and during floods, it could rise over 20 meters or more. In fact in 1841 when a glacial dam across the Shyok River burst, the river rose 30 metres at Attock and washed away a Sikh Army camped upstream on the Plains of Charch. Therefore the engineers selected a site that would give the rail/road bridge headroom of 30 metres above the low water level. The bridge was to be constructed in five steel spans with the two of 95 metres being the longest in India at that time. The main challenge was laying the foundation of the only pier that was in the river channel that had to rest on a rocky shoal. Working in the fast-flowing icy cold water, it took a year for a cofferdam to be constructed (a watertight enclosure pumped dry to permit construction work below the waterline). When the water was pumped out, the condition of the rock that was revealed at the bottom was alarming. It was badly honeycombed and deeply fissured – highly unsuitable for a pier foundation. But time was short and the girders and trestles had already arrived from Britain. The area inside the cofferdam was filled with concrete and work commenced on erecting the pier.

The piers were not like the ones we see supporting the Attock Bridge today i.e. huge structures of masonry and concrete. Good building stone at the site was scarce and instead trestles of riveted wrought iron (like pylons) were constructed, which were considered better at withstanding earthquakes. The working speed was enviable, with all four trestle piers erected in as many months. The erection of the timber staging and the spans on top of them were completed within six months during the winter of 1882-83 though time was lost due to bad weather. Work had to stop when rain and winds numbed the hands and feet of the laborers. Shortly after its completion, a massive earthquake displaced the girders on the trestles by an inch but there was no damage and in May 1883, the first locomotive passed over the bridge.

Sikh and Muslim, two brilliant inspectors, barely able to read and write in English, carried through to successful completion one of the greatest bridge reconstruction works ever taken in India

The entire construction was carried out with no pneumatic tools or electric drives. Rudyard Kipling, who visited the Kaiser-i-Hind Bridge at Ferozepur during its construction four years later in 1887, describes a scene that could resemble Dante’s Inferno and would have been similar to the Attock or any other iron and steel bridges that spanned the rivers in India:

“A few hundred workers are hard at riveting. The clamour is startling, even a hundred yards away from the bridge; but standing at the mouth of the huge iron plated tunnel, it is absolutely deafening. The flooring quivers beneath the hammer-stroke; the roof of the corrugated iron nearly half an inch thick which will form the floor of the cart-road, casts back the tumult redoubled: and it bounds and rebounds against the lattice-work at the side. Riveters […] work like devils; and the very look of their toil, even in the bright sunshine, is devilish. Pale flames from the fires for the red hot rivets, spurt out from all parts of the black ironwork where men hang and cluster like bees; while in the darker corners, the fires throw up luridly the half nude figures of the riveters as they bend above the fire-pots, or, crouching on the slung support, send the rivets home with a a jet of red hot sparks from under the hammer-head.”

The first Attock Bridge lasted well for nearly 40 years, but by 1921, the spans had become distorted and girders were seriously over-stressed.  While the management was considering options, trains were restricted to a speed of 8 km/h on the bridge and heavy road traffic was not permitted when a train was crossing overhead. The most expensive option was to construct an entirely new bridge downstream with a central span measuring a huge 200 meters. Finally, after four years of deliberation, it was decided to entirely replace the two 95-metre spans and strengthen the three 80-metre spans with the structure supported by concrete and masonry piers. However when the bedrock of the pier in the water channel was exposed for a second time, the engineers again received a shock. For 3 metres on the downstream side, the island had been eroded like a bad tooth and half of the trestle was resting on an overhang of a decaying rock! The railways were extremely fortunate that it had survived for so many years.

Therefore an entirely new foundation was constructed with concrete reinforced with tons of rail pieces to support the massive 17,000-ton concrete and masonry pier that encased the old trestle and was designed to take a double railway track. The steel work for the two 95-metre spans had arrived before the end of November 1928. The British resident engineer on site was ably assisted by two bridge inspectors, Sardar Sahib Prem Singh and Karam Elahi, whose skill in bridge-building would become famous throughout northern India.

Sikh and Muslim, these two brilliant inspectors, barely able to read and write in English, carried through to successful completion one of the greatest bridge reconstruction works ever taken in India. With their respective gangs working in friendly rivalry from the two ends of the bridge, in under four months the spans were completed and all the erection gear dismantled and sent away. During the next monsoon season, there were two massive floods in the Indus. The first was again due to the bursting of a glacial dam on the Shyok River and the second was caused by a flood in the Indus combined with heavy rains in the catchment areas of the River Kabul and the Haro. If the damage to the foundation of the river pier had not been detected and repaired in time, most certainly the mighty Attock Bridge would have been washed away.

When Lord Roberts became Commander-in-Chief India in 1885, he advocated the idea that to defend northwest India, troops would have to be concentrated at two points – Peshawar and Quetta. He therefore formed two army commands one for each axis, Northern and Southern. Aligning with this strategic policy, the Scinde, Punjab and Delhi Railways (which were stockbroker companies registered in Britain) were purchased by the Government and amalgamated to form the North Western Railway (NWR). By 1880, a railway line from Karachi along the western bank of the Indus had been constructed till Sukkur and on the far side extended across the waterless desert to Sibi. The first line to Quetta had also been opened in 1886 and there was now a need to link these lines with the Lahore-Rohri Section that had been constructed by the Indus Valley State Railway. At Rohri the Indus flows through a gap in a range of low limestone hills and a steam ferry would transport eight wagons at a time across the river – a process that was slow and unwieldy.

Bridging the Indus at Sukkur had been on the cards since 1872 and for the next ten years various designs had been considered including a suspension bridge with cables formed of steel links. Bridging the smaller channel of 180 metres between Sukkur and the island of Bukkur was straightforward, since its rocky bottom provided a solid foundation for masonry piers. However, the wide and deep Rohri channel of 260 metres that was filled with silt posed a problem for constructing piers. In spite of this, in 1882 it had almost been decided to construct a bridge with spans of 75 metres resting on masonry piers, when a sever flood further deepened the channel to 30 metres.

Sir Alexander Rendel, one of the best civil engineers available, was asked to submit a design without piers. He already had two major railway bridges to his credit: the Alexandra Bridge and the Empress Bridge, but both consisted of spans supported by masonry piers. He proposed a very unusual design of two anchored cantilevers, each 95 metres long, carrying a suspended span of 60 metres in the middle. In spite of an unusual structure, the design was accepted and a contract awarded for the material. Prior to shipping the steelwork, the contractors had assembled the 50-metres-tall cantilevers in their yard in UK, much to the amazement of the spectators. With most of the pre-fabrication undertaken back in Britain, the builders on site were often accused of being little more than “Meccano engineers”. But the reality was that “erection was a demanding task that stretched the ingenuity of the engineers and the safety of the workers.”

This was particularly so in the case of this bridge and there were even doubts as to whether the designer had actually consulted the engineers sufficiently. Much praise is due to Robertson, the executive engineer of the Bridge Division of the Indus Valley State Railway, and his team. Above all, the credit goes to the 6,000 workers employed there, for getting 3,300 tons of the most awkwardly designed steelwork into place within two and a half years. It seemed that Sir Rendel had almost gone out of his way to test the ability of the engineers who had to construct two giant derricks each weighing 240 tons (of 5-ton segments), that extended 70 metres over the water while simultaneously leaning inwards. To attach the horizontal tie girders of 86 tons, laborers had to work at a height of 55 metres and four fell and died during construction. According to the original design, the 60 metres-long centre span was to be floated out and hoisted up but the idea was impractical as the speed of the current was too high for half the year. Therefore Robertson built a temporary bridge on which the suspended span was erected and put in place.

It was inaugurated in 1889 and named Lansdowne Bridge after the Viceroy. It was the longest rigid girder bridge span in the world but its design was subsequently described as “bizarre[,] neither economical in weight of material nor cost of shop work”. Because of the rigid nature of the joints at the end of the members, the bridge suffered high deformation and temperature stresses. Therefore from 1924 onwards, the speed of trains across the bridge was restricted to 8 km/h.

To replace the bridge, a number of designs were considered before and after Independence and ultimately in 1959, work commenced on a single arched structure with a span of 250 metres that was designed by American consultants. The bridge was constructed only 37 metres downstream from the Landsdowne Bridge and was the first bridge in the world to have the railway deck slung on coiled wire ropes. It also had the third longest railway arch span in the world that was not only functional but also graceful. Interestingly it used the same amount of steel as the Landsdowne Bridge but was much stronger and could bear heavier train loads at greater speed. It was named after President Ayub Khan, who inaugurated the bridge in 1962.

Though there was a bridge at Attock and Sukkur, there was no crossing over the Indus in the gap of 800 km that separated the two. A large cantonment at Kohat was being established but it could only be supported from Peshawar and accessed over the Kohat Pass. A crossing existed at Khushalgarh (70 km below Attock) that was served by a bridge of boats which had to be dismantled when the river rose in summer. A railway line was extend from Rawalpindi to Jand and in 1902 a cableway powered by a steam engine was constructed that, at its best, could transport a narrow gauge wagon with a 1.5-ton load. However as a result of poor maintenance an anchor gave way in 1903, plunging a wagon into the river. And so it was decided to construct a rail/road bridge.

The Indus at Khushalgarh flows through a gorge 30 metres deep and 250 metres wide. The width was too large for a single span but fortunately a headland jutted out from the eastern bank that was exposed in winter, on which a pier could be constructed to support the structure. The design of a two spanned rail/road bridge was prepared by the same team of Rendel and Robertson who worked on the Landsdowne Bridge. The eastern span was an anchor span that rested on a massive masonry pier erected at the extreme end of the headland. From this support, a section was cantilevered out 32 metres and another cantilever of similar length was anchored in a cliff at the Western end. Between the noses of the two cantilevers, a span of 80 metres was slung. The finished bridge therefore had only two spans – one of 144 metres and a second of 92 metres – both resting in the middle on the large masonry pier.

The order of the first consignment of the 2,000 tons of prepared steelwork required for the bridge was ready for shipping within three months. The entire order was met within 8.5 months which was a remarkable speed of manufacturing the anchorage, cast steel girder bearings and the steel work for spans of a 236-metre double decker rail/road bridge. Compact limestone with good weathering properties for the pier and abutments was brought by rail from Hassan Abdal and the Margalla Hills. The substructure work including the pier and abutments was completed in the winter of 1905-6 and the main bridge was completed within two more years.

From 1883 onwards, in less than 50 years the British constructed five major road/rail bridges across the mighty Indus including two multi-span bridges resting on piers at Kotri (1900) and Mari Indus (1931). Many of them, including the ones constructed across the five rivers of the Punjab, were subsequently strengthened to take heavier loads at greater speeds without upsetting the schedule of trains. It goes to the credit of the British engineers as well as the Indians that they trained like Ganda Singh and his grandson Naurang Singh (the head draughtsman in the Bridge Department of the NWR who retired in 1945).

Even 100 years later, these bridges are still standing and the majority are still serving Pakistan and its railways. But there is a darker side to the development of railways in India – a story of greed and exploitation and callous disregard for the masses traveling in Third Class and a lot more that has been brought on record by historians.