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In consequence of the absence of all navigable streams and of every mode of transport except by negro carriers, it was necessary to adopt what is here termed the "Telescopic" system, for the construction of the line; that is to say, that the railway itself had to provide all the materials for its extension, by means of the section already constructed, and all fresh supplies had to be pushed forward from the base. Even the workers themselves had to be recruited and lodged and fed by the Company, in special camps constructed as the works proceeded, for the country in the region of the cataracts is very sparsely inhabited, and it was at all times impossible to advance more than from 7 miles to 9 miles beyond the end of the rails. It may readily be imagined that vast difficulties had to be overcome in thus constructing a railway in an unknown country with wholly unskilled workers, who had never seen a pick or a shovel, under climatic conditions, moreover, of the most unfavourable kind. Still for several years the railway was pushed forward at the rate of from 60 miles to 72 miles annually, and although critics, who were not familiar with the real circumstances of the case, have been disposed to cavil at certain of the details, all those who have studied the railway on the spot have been enthusiastic in their praises of the undertaking.

As soon as the works were actually taken in hand, the preliminary survey was only looked upon as furnishing a general idea of the line to be followed, and any possible improvements which became apparent as the railway proceeded were invariably adopted. From the 56th mile onwards it was decided to reduce the maximum gradients from 45 per 1,000 to 40 per 1,000, and to increase the radius of the curves to a minimum of 3 chains.

The surveying party in advance of the excavators, who went forward to stake out the centre of the line and to drive in posts to mark the levels of the formation, had to see that the grass was cut down, for otherwise this constituted an almost impenetrable jungle, attaining during the rainy season to a height of from 10 feet to even 20 feet. They had also to construct light foot-bridges over the streams and ravines to permit of the passage to and fro of the workpeople, and lastly they had to select and prepare the spots chosen for the camping-grounds. The soil in the regions traversed by the railway is very varied in character, but little hard rock was encountered until Palaballa (10 miles) was passed. Towards the 140th mile there exists some rocky ground of intense hardness, which had to be blasted with dynamite. Though much of the ground was very firm, it yielded readily to the pick, but some beds of tough clay were found which crumbled on exposure

to rain and to the atmosphere. Very few of the cuttings were made in vegetable soil, as the line followed for the most part the spurs of the hills, denuded by tropical rains. A photograph of one of the deep cuttings is given, to show the nature of the excavations. Along the banks of the Congo and the M'Poso, that is to say, for the first 5 miles, the construction of the railway on the face of the rocky cliffs was a work of much difficulty and even danger, and the workmen had in some cases to be slung from above by means of ropes. The line in these places follows the bed of the torrent in a species of semi-tunnel formed in the rocks at a height of from 130 feet to 160 feet above the stream, the mere elevation causing giddiness to those unaccustomed to similar scenes. It was necessary also in some instances to build up lofty foundation walls from below to carry the line which projects beyond the face of the cliffs.

The picks and shovels used by the negro workers were of the usual make, but somewhat smaller in size than those generally employed. Small barrows with cast steel wheels were made use of in the cuttings, and in certain of the deeper and longer excavations and embankments iron tip-wagons, holding about 9 cubic feet and running on a portable rail with a gauge of 16 inches, were introduced with success. The individual work done by the negro excavators was at first very small, but it improved ultimately up to 3 cubic yards per diem, mainly under a system of premium payments founded on piece-work. The Author recommends this system for all work of a similar character, whatever may be the race of work people employed. In connection with the excavators' work two special gangs were employed, the one charged with the preparations for the bridges over the ravines and rivers, and the other having to deal with the construction of the metallic culverts and the trimming of the embankments. Rough timber trestlebridges of given dimensions were in the first instance erected, and it may seem strange that, in a country which abounded with forests, it was found cheaper to employ imported European wood than to prepare squared timber on the spot. A photograph shows the character of the trestle-bridges adopted. With respect to the metallic culverts, it is stated that these no doubt constituted one of the chief factors in the possibility of speedily constructing the railway. As a matter of fact, though the bridges are fairly plentiful on this line, the small watercourses and channels may be said to be innumerable, and as in every case it was necessary to confine and train the waterways, the use of a multitude of small culverts (aqueducts) under the line was unavoidable. Masonry in

Africa is very dear, and the negroes are very slow in constructing arches and vaults. If all the culverts under the line had been built in stonework, it would have been impossible to attain to any great rapidity in completing the railway. It was originally proposed to carry out these culverts in compressed concrete, but the cost for freight was excessive. It was found also after a short trial that concrete castings were not strong enough to stand the rough handling during the voyage from Europe, and that a very small fraction of the consignment arrived at the works intact. Under these circumstances it was resolved to make use of steel tubes, which were supplied in two dimensions, the smaller 19.7 inches in diameter, in lengths of 23.6 inches, and the larger 39.3 inches in diameter, in lengths of 31.5 inches. These tubes were formed of mild sheet-steel, varying in thickness from 0.15 inch to 0.35 inch. They were riveted together and made to taper slightly, and the sizes were so adjusted that three lengths always fitted one within the other, for the sake of saving in freight. Each end is fitted with a hoop, to ensure a good joint, and at first the tubes were jointed with Portland cement; subsequently joints of tow and red lead were used instead, but latterly all jointing has been dispensed with, as the earth soon washes into the interstices between the tubes and becomes consolidated. The Author shows that the objections as to want of durability urged against this mode of forming the culverts have not been established in practice. Although the gauge was first fixed at 29.5 inches, the rails as actually laid have a gauge of 30.1 inches. This small widening was decided upon as being that required for the maximum curvature. The line abounds with sharp curves, involving constant slight changes of gauge, and as it would have been difficult to avoid errors in the dimensions, it was ultimately decided to adopt the above extended standard gauge throughout. The rails weigh 43 4 lbs. per yard, and were supplied in lengths of 23 feet to suit the trucks. Some shorter lengths were furnished to serve for the inner rails on curves of 2 chains. A Table is given of the elevation of the outer rail for curves of various radii, calculated for a normal speed of 18.6 miles per hour, these elevations varying from 2 inches on a curve of 2 chains down to 0.2 inch on a curve of 25 chains.

Two descriptions of fish-plates were at first used, flat-plates and angle-plates, but the former were soon given up, because they were found unfitted to stand the heavy strain on the curves. All but the first few miles of rails are therefore jointed by means of double angle-fish-plates. The rails are of semi-mild steel, the

fish-plates of mild steel, and the bolts of iron. The sleepers are of the "Ponsard" type, of rolled mild steel, weighing 71 lbs. each, and they receive while hot a coating of tar. They can be handled by one man, and can be laid very rapidly. The rails are fixed to the sleepers by two tee-headed bolts, screwed into a binding-plate beneath. They rest on wedge-shaped bearingplates, riveted to the sleepers, giving the rails an inward cant.

The stores sent up on trucks from Matadi were unloaded at temporary depot-wharves near the rail-end, and moved forward from time to time as the work advanced. The locomotives employed while the line was being constructed were of the type known as "works engines," of the same description as those used for haulage before the ballast was laid. Special patterns of points, crossings, and switches were employed, which were made in three pieces in Europe, and were very rapidly put together where required in less than an hour each. All crossings are of one uniform angle, 7° 45', and the points are 8 feet 2 inches in length. The sidings signals are simple disks of the usual pattern, placed at from 220 yards to 330 yards from the sidings, and controlled by levers of the ordinary type. The water-towers, of a capacity of 2,200 gallons, are situated at convenient distances apart, and possess in each case a water-crane attached to them. The supply to the towers is by means of hand-pumps of the "Californian " type. Attempts are being made to provide for water in larger quantities, and the use of windmill pumps is proposed. Over parts of the line in certain seasons it was difficult to obtain water, and to overcome this drawback three tenders were constructed, each capable of carrying 660 gallons. They were made of a special pattern, so as to serve at the same time as wagons, but so far they have not been used.

All the masonry employed was of the nature of rubble-work, squared stone not being available. Slaked Tournai lime and cement were brought from Europe, and the sand was procured from the beds of the torrents. The mortar consisted of two parts of lime, one part of cement, and three parts of sand. This mixture was very rich, but the importance of strength was permitted to outweigh the question of economy.

Whatever might be the span of the bridges, the chief consideration was the need of avoiding intermediate piers, owing to the torrential character of the streams. Only two of the bridges contain more than one span, the one having a clear width of 229.6 feet, and the other of 196.8 feet. In these cases no other course was open, because it was found after the ironwork had

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