The viaduct was built upon the overhanging principle, in accordance with the American practice, by means of a traveller. This was a cumbersome piece of apparatus weighing 100 tons, with a long arm which reached out over the gorge from tower to tower. To the native this appliance was a source of infinite wonder. When it was pushed out to its fullest extent, and the long arm appeared certain to lose its balance and to topple into the ravine, they looked on with awe; and when the Americans flew in the face of Providence, as they thought, by venturing to the outermost point to carry out their work, they shuddered. In fact, they never became accustomed to that traveller. Why it did not capsize exceeded their comprehension.
The American workmen were assisted in their operations by 350 natives brought from other parts of the country, and who were accustomed somewhat to bridge-building. Once work was brought into swing, it went forward with a rush, the steel towers springing up from their pedestals to a height of 200 feet or so within two or three days. The men toiled 9¾ hours every day, and there was not a halt except when the monsoon blew and it was well-nigh impossible to secure a foothold in exposed positions, or when the torrential rainfall prevailed.
The white men found the heat particularly trying and exhausting. Those perched 200 or 300 feet in the air, and fully exposed to the sun and a temperature of 120 degrees, secured a little welcome shade under an awning that was stretched over the apparatus. They wore the lightest of clothing, while white pith helmets served to offer some protection from sunstroke.
The total length of the work is 2,260 feet, and it is built up to 10 spans, each measuring 120 feet, and 7 spans of 60 feet apiece. The girders forming the deck are supported on steel towers spaced 40 feet apart. The height of the rails at the highest pier is 325 feet above the floor of the gorge, and 825 feet above the Chungzoune stream. No less than 232,868 separate pieces of steel had to be handled on the site, and the natives had to drive 200,000 rivets to secure the fabric together.
Owing to the remote point at which work was being carried out—10,000 miles by sea from home—an elaborate cable code was drawn up, each integral part of the viaduct, as well as details of the erecting plant, having a distinctive word. In addition, there were special words for the purpose of reporting the progress of the erection to headquarters. Every week the chief engineer cabled home a full progress report at a cost of 5s., or $1.25, per word. The men were provided with a well-equipped medicine chest, and a complete photographic outfit constituted an important part of the organisation, photographs being dispatched to Steelton regularly to supplement the cabled and written report on the progress of the undertaking. Only one man was lost in the enterprise, and this was attributable to fever produced from indulgence in alcoholic liquor. No other fatality was recorded either among the natives or Americans, and no serious accident marred the work, which, bearing in mind its magnitude and character, was highly satisfactory.
The actual erection occupied nine months, work being continued uninterruptedly through the wet season, when, fortunately, the greater part of the annual 150 to 200 inches of rain fell during the night. Although the viaduct is 24½ feet wide across the top, which is sufficient to carry a double track, only one road is laid at present. The bridge also enables pedestrians to cross from one side of the chasm to the other, refuge platforms being provided at frequent intervals to enable those afoot to escape being run down by passing trains. Upon completion, the structure was subjected to severe tests spread over a period of two months, and these proving satisfactory, the structure was accepted by the railway authorities. The mammoth steel traveller weighing 100 tons, and which had played such an important part in the rapid erection of the viaduct, was demolished and sold for scrap.
By the provision of this viaduct at the selected height the track is led to a natural ledge on the opposite cliff-face. While the viaduct was under construction the railhead was pushed forward, the material for the grade being transported across the valley by the overhead cable. By the time trains were able to cross the structure, the end of steel had reached a point some 35 miles beyond.
Although the viaduct is not so lofty as other structures of its class in other parts of the world, yet it occupies a position of distinct importance. Moreover, it constitutes one of the finest expressions of this class of American work that has ever been fulfilled.