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The German East African Central Railway. VoN SCHWABE. (Annalen für Gewerbe und Bauwesen, 1 October, 1898, p. 125.)

The Committee for the above railway reported on 19th June, 1896, that either by State aid or at the cost of the State-it was of the utmost importance that a railway should as soon as possible be constructed from Dar-es-Salâm to Ukami, with a junction to Bagamayo, as the first section of a line joining the German littoral in East Africa with the lake districts of Victoria-Nyanza and Tanganyika. The estimated expenditure for the first section of the above line was £592,500, and it was probably chiefly on the score of the cost that the project has hitherto remained abortive. Reference is made to the proposals for other German colonial railways, and to the scheme for the English line from Mombasa to Lake Victoria-Nyanza, likewise to the colossal project of a railway to be undertaken from Buluwayo to Lake Tanganyika by the Chartered Company. Attention has recently again been directed to German colonial enterprises by the speeches of Mr. von Bennigsen, and the Author proposes to give further details concerning the Central African railways. Sketch profiles are given of the English Uganda Railway, the projected Northern-German line and the Middle-German line to the same scale, the total lengths being respectively 656 miles, 497 miles and 909 miles. A proposed southern line, advocated by Governor Freiherr von Scheele, is here, for reasons given, omitted. Various estimates of the cost per mile of these different lines have been put forward, but it is shown that at the actual minimum outlay on the Uganda Railway of £2,700 per mile, the Central German line, which, with its branches, has a total length of 1,086 miles, would need an expenditure of upwards of £2,940,000. Some account is given of the colonial imports and exports and of the growth of revenue from 1891 onwards, and various considerations follow respecting the best methods of developing the resources of the country by the use of waterways to the utmost extent, and by the improvement of the roads and caravan routes to the interior. Allusion is also made to the Author's plan for a narrow-gauge railway using the common roads.

Swiss Railways of the Rack-Rail System.

E. STRUB, Civil Engineer, Interlaken.

G. R. R.

(Organ für die Fortschritte des Eisenbahnwesens, 1898, p. 140.)

The first three of the eleven railways referred to in this Paper are of the standard 4 feet 8 inches gauge, with long radius curves and two-axled vehicles. These lines did not pay, and this checked for a time the further extension of the system until, in 1898, the

Pilatus Railway gave a fair return for the capital invested; the width of gauge having been reduced, and radii of curves increased about half, thus allowing the employment of locomotives with three, and carriages on four, axles. These reductions proved too great, and the gauge in later times was increased to 3 feet 33 inches, and the minimum radius to 80 and 90 metres. Electricity supplanted steam-power, and the locomotives and cars were combined without greatly increasing the cost, while the carrying capacity was doubled and the safety increased. The Gornergrat1 and Jungfrau lines are now capable of carrying twice as many passengers with the same dead weight as the first five railways. Experience has shown that the increased radius should not be less than 550 yards, nor the gradients more than 1 in 4, and gauge not less than 3 feet 3 inches. The permanent way since the reconstruction of the original lines is fundamentally the same in all— 3.93 inches height of rail, weight 40 32 lbs. per yard, with castiron sleepers bedded in concrete. There are four distinct varieties of rack-rails, the latest, that on the Jungfrau line, is on the Strub system (described at page 151 of the Organ for 1897), and combines the safety of the "Pilatus," the durability of the "Luter," and the lightness of the "Platten" systems, without any of their defects. The locomotives are of five varieties. The carriages are built mostly on one system. A Table in the Appendix gives at a glance the principal details of eleven Swiss railways worked on the rack-rail system.

W. A. B.

The Electric Rack-Railway on the Gornergrat.

(Schweizerische Bauzeitung, 1898, p. 116 et seq.)

This is a long and detailed descriptive article running through Nos. 16 to 21 inclusive of the journal. It is pointed out that until comparatively recently Zermatt, Visp, and Wallis were difficult of access. Whereas in 1838 there were only about twelve tourists in Zermatt, there were in 1894 about 20,507. From Zermatt many tours are made, and the Gornergrat, 10,200 feet high, is one of the chief resorts. It was considered desirable therefore to connect this point with Zermatt by rail, and a sketch of the history of the undertaking is given. The firm of Haag & Greulich undertook the work, and prepared plans in 1894. was thought possible to employ the power of waterfalls and to work the line by electricity, and though the initial cost would be higher than if steam-power were used, the cost of maintenance would be much less. The line is about 5.6 miles long, and the cost was estimated at £130,000, and maintenance at £3,360 per

1 See next Abstract.

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annum. On the 11th January, 1896, the tender of Messrs. Haag & Greulich was accepted to construct the line for the sum of £120,000, including rolling-stock and electrical equipment. The terminus at Zermatt is 5,300 feet, and the Gornergrat Station 9,900 feet, above sea-level, which is the highest point yet reached by any railway. The total rise is therefore 4,600 feet in 5.63 miles, and the steepest gradient is 1 in 5. The journey occupies 90 minutes, and 110 passengers are carried at once. Tunnelling was carried on all through the winter of 1896-7 by 150 men, and as many as 1,100 men have been employed at once.

Mountain sickness became common at the summit. The various forms of road-bed are described and illustrated, and details are given of the construction of several bridges and tunnels. The gauge of the line is 1 metre, and the sleepers are of steel, with the Abt double rack. For the power installations tenders were invited from the chief European electrical firms. The result was that Brown, Boveri & Co. supplied the electric plant, T. Bell & Co., of Kriens, the turbines, the Swiss Locomotive Works, Winterthur, the locomotives, and a Neuhausen firm the carriages. The water-power plant at Findelenbach consists of three highpressure Girard turbines running at 400 revolutions, and each capable of developing 250 HP. One of these is a reserve plant. The electric plant is on the three-phase system, and the generators are coupled direct to the turbines. The exciter is also driven by a turbine. The potential is 5,400 volts at forty periods per second, and feeders are carried to various points on the line where the potential is transformed down to 540 volts for use. Each locomotive weighs 10.5 tons, and has two motors of 90 HP.

E. R. D.

Power Consumption on Electric Railroads. S. T. DODD.
(Journal of the Association of Engineering Societies, August, 1898, p. 68.)

In considering the power necessary to propel an electric streetcar, the Author first investigates the frictional resistance, and arrives at the following formula, which fits the result of about twenty of the most trustworthy observations he could get, for the resistance in lbs. :

(20.16 0.22 V) E+ (7·84 + 0·22 V) T,

where V is the velocity in miles per hour.

E the weight of engine or motor car in tons.
T the weight of trailing cars in tons.

1 The summit tunnel of the Lima and Oroya Railway in Peru is 15,600 feet above sea-level. Minutes of Proceedings Inst. C.E., vol. lv. p. 388.—SEC.

INST. C.E.

He next shows that the force in lbs. per ton required to accelerate the car equals

102.3 × F,

when F is the acceleration in miles per hour per second. This he compares with the force required to mount different gradients; and the Paper concludes with a number of numerical examples. A. W. B.

Improvement in Railway Couplings.

H. WICK, Chief Foreman Bavarian State Railways.

(Organ für die Fortschritte des Eisenbahnwesens, 1898, p. 97.)

The Author assumes the strain developed, under ordinary circumstances, by a goods locomotive to be equal to about 5.9 to 6.9 tons, and very much greater under certain exceptional conditions. The safety of the traffic and the comfort of the travelling public call for the more general employment of continuous drawbars that will relieve the wagon-frames of all unnecessary strains and afford greater elasticity. The arrangement illustrated in this Paper, it is claimed, fulfil these requirements. The two drawbars are coupled and keyed together; each is provided with a spiral spring capable of a resistance of 7.87 tons; these springs are fixed back to back and are allowed 6 inches play. One of the springs is inserted under compression equal to 330 lbs.; the other under compression equal to 3,300 lbs. With this arrangement, as the strain comes upon the draw-bar, the first spiral spring is compressed until the strain exceeds 3 tons, when both springs come into play, and act as long as the strain does not exceed the combined resistance of both springs.

W. A. B.

Electrical Locking-Bar.

(Organ für die Fortschritte des Eisenbahnwesens, 1898, p. 157.)

With a view to the more effectual protection of trains standing in or passing through a railway station, Messrs. Lorenz, of Berlin, have brought out an electrical arrangement by which a signal is shown for every line occupied. Parallel to, and on one side of the rails, shaped rails on spring chairs are fixed; these rails are rather longer than the extreme wheel-base of any wagon or carriage. An iron box, containing the mechanism (which is fully described), is bolted to the piece, and moves on a pivot whenever the outer flange of any wheel comes upon it. This movement breaks electrical contact, interrupts the current, and works the

tell-tale. All the locking-bars on one line of rails are connected up in one circuit, so that as long as any vehicle is on that particular line its signal stands at danger. These rails are so balanced that pressure on any part of them is sufficient to work the signal. The spring chairs, however, offer such resistance that nothing less than the weight of a wagon depresses them; at the same time they are so elastic that an express train passing over them in no way injures the mechanism.

W. A. B.

Automatic Electrical Block System.

(Organ für die Fortschritte des Eisenbahnwesens, 1898, p. 161.)

The electrical locking-bar, described in the preceding abstract, has been further adapted and extended so as to record by visible and audible signals the entrance into and occupation, by a train, or single engine, or wagon, of any particular track of rails, at the same time preventing the signals being lowered, and the points moved, as long as there is any vehicle standing on the line. Further, it automatically locks the lever-handle of any switch or signal, and frees it only when the rails are clear.

The locking-bar is connected electrically with the apparatus in the signal-box or station building. The current is always on; the connecting wire passes round an electro-magnet, the armature of which engages a stop on a disk actuated by a weight. When an engine or wagon depresses the locking-bar the circuit is interrupted, the armature freed, the catch disengaged, and the disk revolves through 90° and is then arrested by another stop. This movement causes a danger signal to appear, and starts a sounder; at the same time the outside signals and points are worked and locked. When a train or wagon clears the track, the locking-bar rises and again closes the circuit, the signals and points are released, and things return to their normal position. This process is invariable and the failure of any part is at once indicated. If the current is too weak, or the connections at fault, the armature is released and the line is blocked. The force exerted by the electro-magnet is equal to 60 grains. One winding up of the weight is sufficient for 320 trains; before it descends to its lowest position a sounder rings, and the points and signals are set at danger, so that every possibility of accident is provided against. The whole mechanism is minutely explained in the letterpress and by four diagrams.

W. A. B.

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