The spans are supported on masonry piers, each 18 feet wide by 8 feet thick. Mr. Lawley found the river-bed to be composed of rock and gravel, which gave a first-class foundation, and favoured the expeditious erection of the piers. Consequently he concluded, if the piers were pushed forward at low water, that it would be possible to set the steel-work directly the river once more gained flood-level, and arrangements to this end were carried out. Timber coffer-dams were built around the sites for the piers, and by the aid of pumps the interior was kept clear of water to permit the workmen to achieve their stone-setting task within under the most favourable conditions.
While the piers were progressing other gangs of natives were hard at work in the improvised shipyard riveting the steel-work together. Each span measured 100 feet long, 14 feet in width, 20 feet in height, and weighed 56 tons. The pontoon itself measured 95 feet long by 45 feet wide.
Work continued so favourably that by the time the masonry work on the piers was completed the spans had been assembled, and all was ready for transhipping them from the yard to their respective positions on the piers. Novel means for transporting the weighty and bulky masses of steel were adopted. The pontoon was brought endwise against the river bank and made fast. A length of railway track was laid from end to end along the deck of the pontoon, and was brought against the ends of another short track running down the river bank, thereby making a continuous length of railway line. As the completed spans were ranged side by side in the yard at right angles to the river, they had to be hauled sideways for some distance. Rails were laid under each end of the spans at right angles to the railway and were well greased so as to become a kind of “ways” such as are used to launch a vessel. Gangs of natives tugged at the span to haul it broadside until it rested on the railway line, which also was lubricated. Then two locomotives were brought up to the rear end of the span, and by sheer steam force pushed it down the bank railway on to the pontoon, where it rested fairly and squarely, and overhanging equally each end of the pontoon, which was five feet shorter than the span.
The pontoon was then released from its moorings and was hauled out into the stream by means of the endless cable, until it came centrally between the two piers on which the span was to be placed. From each pier a hawser was passed to stanchions on either end of the pontoon. The endless cable was slackened, and the pontoon, with its novel cargo, was permitted to drift slowly down-stream towards the space between the two piers, being guided in its course by manipulation of one or the other of the two hawsers. In this manner the craft was steered delicately into position and was made fast. The actual transference of the span from the pontoon to the masonry bed was carried out by hydraulic jacks, which lifted the whole mass of steel. When the jacks were released, the ends of the span rested firmly on the two piers. By hauling on to the endless cable the pontoon now was drawn clear of the bridge to return for another load.
This novel method proved so completely successful that the 13 spans were transferred from the bank and set in position within the short space of 8 days!—half the time the engineer had computed as being requisite for the operation. The whole undertaking was accomplished in record time, bearing in mind the peculiar conditions prevailing in the heart of Africa, and the use of native labour; for, from the time the first move towards the erection of the piers was made, to the setting of the last span, only five months elapsed. The total cost of this mass of steel, weighing 728 tons and stretching in an unbroken line for 1,300 feet across the river, was £50,000, or $250,000.
When Broken Hill was gained, 2,013 miles from Cape Town, construction was brought to a stop. The mastermind had passed away some time before, and the colleague who had assisted Rhodes when other financial magnates turned a deaf ear to the project, had also joined the great majority. By the time Broken Hill was gained, £8,000,000 (or $40,000,000) had been sunk in the enterprise. For months the stack of 2000 tons of steel for the resumption northwards remained untouched, through lack of funds, though Mr. Alfred Beit had left £1,500,000 (or $7,500,000) towards the continuation of the work. Then the mineral wealth around Katanga in the Congo Free State, which was under exploitation, demanded transportation to the coast. Accordingly, the line was pushed on to the border of the adjacent country. Rhodes’ objective was Kituta, at the southern end of Lake Tanganyika, 450 miles north of Broken Hill, which point marks the limit of British sway in South Africa, a distance of about 2,700 miles by rail from Cape Town.
When Rhodes’ vision presented the railway stretching in an unbroken thread from north to south, the knowledge of the country lying between the Zambesi and the Nile was somewhat scanty. As the scheme progressed it became known that Lake Tanganyika was hemmed in by precipitous mountains, where railway-building would soar to an enormous figure per mile. On the other hand, the lake is a splendid sheet of water, offering excellent navigation throughout its length of 400 miles. Therefore, there should be no reason why the example of the Russian Government, in regard to the use of ferry steamers on Lake Baikal, should not be emulated to transport trains intact from Kituta at the southern, to Usamburu at the northern, end of Lake Tanganyika.
Ninety miles north of Usamburu is Lake Kivu, and the dividing neck of land offers no great difficulties to construction beyond a gradual rise of 2000 feet. Reaching Lake Kivu, which is also surrounded by lofty ridges, the railway would once more take to the water for some 60 miles. Continuing northwards, there is another stretch of rising country to be crossed, where the track would be lifted to its greatest height, or summit level, between Cape Town and Cairo, to gain the head of Lake Edward, which is 75 miles in length. Owing to the flat character of the country around this sheet of water lending itself to cheap railway construction, probably it would be found preferable to keep to the land, especially as the country is healthy, thickly populated, and offers great promise of becoming wealthy under commercial development.
But the line, after leaving Lake Kivu, has to pass through Belgian territory, and as this location is inevitable unless it were decided to swing somewhat to the east to pass through German East Africa, an easier route has been offered through the Congo. The railway has been taken from Broken Hill to Elizabethville. The Belgian authorities are anxious that it should be extended from that point to Bukana on the Congo River. Boats could be used between this point and Congolo, where communication by rail would extend to Kindu, to be followed by another stretch of river as far as Ponthierville. The existing railway to Stanleyville would then be pressed into service, and from the last-named point the line would debouch to the north-east to gain the Albert Nyanza, and there link up with the railway that has been driven southwards from Cairo.