SOUTHERN RAILWAY. [Double-headed rail only employed.] An old type of iron rail 74 lbs. per yard (1857), height 5-27 inches, width of head 2.48 inches, length 18 feet, suspended fish joint, carried on six sleepers; weight of chairs 22 lbs. Similar type in steel 78 lbs. per yard, laid in the same way. J. D. Experiences in the working of Mountain Railways. BY M. STEINSBERG, Manager of the Poti-Tiflis Railway. (Organ für die Fortschritte des Eisenbahnwesens, No. 2, 1874, pp. 61-67.) The construction of engines for steep gradients seems to exclude their adaptability for sharp curves. On the Poti-Tiflis railway the ordinary minimum traffic requires an adhesion upon the rails corresponding to a weight of 90 tons, or taking 15 tons per axle, six axles are required to sustain the adhesive weight. On the other hand, the sharp curves necessitate a wheel base not exceeding 8 feet for curves of 131-chains radius, and of 7 feet 6 inches for those having a radius of 8 chains. Engines able to perform such work, at a mean speed of 12 miles an hour, should be of about 600 HP., and have a heating surface of more than 2,150 square feet; this would involve such a length of boiler as to render it difficult to procure steadiness upon a short wheel base. The great weight required increases the injurious lateral effect of the wheels against the rails, upon curves of small radius, and causes a waste of labour in overcoming the grinding of the outer wheels upon the rails. Another difficulty with engines for steep gradients is to keep the tubes and the top of the fire-box covered with water, this restricts the heating surface necessary for the production of sufficient steam, as in a boiler 22 feet long, on a gradient of 1 in 22, there is a difference of 1 foot in the level of the water surface at the two ends. In engines for sharp curves, in consequence of the small wheel base and the unfavourable position of the boiler, an uneasy rolling motion is unavoidable, and the small diameter of the wheels, necessitated by the short wheel base, greatly increases the resistance to motion of the machine. If this resistance is expressed by the formula p = the weight of the engine without the wheels; the weight of the wheels; the diameter of the axle bearings; = = f = the coefficient of rolling friction 0.001; it appears that the resistance to motion increases not only with the weight of the engine, but also with the reduction of the size of the wheels. These difficulties seem, at first sight, to be overcome by the Fairlie' engine. Theoretically, the entire weight of the locomotive serves for obtaining adhesion, and from its position on two movable frames (bogies), it admits of the short wheel base necessary for passing round sharp curves. By the favourable position of the fire-box at the centre of the boiler, the relation of water level with reference to its top and the tubes is reduced to one-half the difference of level which would exist if the fire-box were placed at the end of the boiler. But these engines appear in another light when they have been observed at work; unavoidable defects become apparent, which are not mere faults in construction, but inherent to the system. The most notable defect is the susceptibility of the steam-pipes to injury. A one-sided raising of the bogie frame, or the small shocks given to it by every alteration in the speed or difference in the level of the rails, affect the pipes at their point of connection. This results from the boilers being attached so loosely to the under frames, that every shock to the latter is injuriously felt by them before being transferred to the upper and greater mass of the machine. This defect became apparent on the Poti-Tiflis railway, where, in consequence of the weakness of the carriage couplings, the trains had at first to be pushed, instead of hauled, up the inclines. The frequent small back shocks to the forward wheel frame of the engine, in consequence of the variations of level or speed, occasioned perpetual injuries to the steam-pipes, so that the system of pushing had to be discontinued, and the number of carriages per train reduced, to enable them to be pulled up with safety. In the engines for the Poti-Tiflis line, the manufacturers had endeavoured to remove this defect by constructing the smoke-boxes of very thin plates, but they had afterwards to be stiffened. Another important evil of the system is that the play or movement of the Fairlie engine is exclusively in a horizontal direction ; that is, in a plane parallel to the rails, no play or movement taking place vertically. Mr. Ramsbottom tried. the engines on a rising gradient, succeeded by a falling gradient beyond; so that on passing the summit the weight was shifted from the forward to the trailing wheels. When this occurs, slipping of the wheels on the rails follows as a natural consequence. This is not only injurious, but dangerous, as tending to throw the engine off the line; for it has long been a recognised fact that the rails do not possess sufficient lateral resistance against a rolling body, unless kept in position by a superimposed weight. The experience derived from the working of the Poti-Tiflis railway gave similar results. Careful drivers observed that during the passage over the mountains in the early morning, when the rails were damp and greasy, the wheels of the leading bogie frequently slipped on iron bridges or viaducts; whereas with the same state of the rails on the ordinary road there was sufficient adhesion to prevent slipping. The Author believes the explanation to be, that there is generally a difference in the level of the rails on iron bridges and on the adjoining embankments. Upon steep lines, therefore, the shifting of a portion of the load from one set of wheels lessens the necessary adhesion on the rails and throws extra weight upon the other axles, to the detriment of the Fairlie engine, especially as, calculating on its easy running, the axles are one-sixth weaker than in ordinary engines of the same weight. The tendency of these engines when thrown off the rails is to diverge, more than locomotives with fixed leading wheels, from the direction of the axis of the line, on account of the movable character of the bogie. This defect becomes more perceptible owing to the super-elevation of the outer rail on curves, which alters the position of the bogie frame, and prevents it from giving the long boiler a proper support; while by partially removing the weight from one rail and increasing it upon the other, the joints of the rails are exposed to dangerous strains. The question of greater cost of repairs is as yet insufficiently known, but it is creating alarm. From the peculiar connection of the boiler with the wheel frames upon which it rests, shocks to the buffers do not distribute themselves equally over the whole machine as in the case of other engines, but are borne principally by the bogie frames. An accident on the Poti-Tiflis railway exhibited this fact clearly; in a collision at high speed between a small tender engine and one of Fairlie's, the latter was greatly injured, while the former was able to resume work. These double locomotives are the more expensive, as one engine is rendered useless while the other is undergoing repairs. Moreover, for every four in stock only two and a half can be kept in working order, or only two where the traffic is heavy, whereas with ordinary engines the proportion is six out of eight. These defects are conclusive evidence that the Fairlie engine ought to be restricted to mountain and mineral lines of secondary importance, and of narrow gauge. Under no circumstances is it suitable for the regular .working of a mountain railway, where safety and regularity of traffic are indispensable. The Author then describes an engine which he elaborated in combination with Herr Schau, Technical Manager of the Sigl works, Vienna. The eight-wheeled coupled engine has a wheel base of 10 feet 8 inches (3.25 mètres), or (omitting the leading and trailing axles, each of which is free to move laterally) a rigid wheel base of 3 feet 6 inches (1.075 mètre), the diameter of the wheels being 3 feet 3 inches (1 mètre). With an effective steam pressure of 9 atmospheres this engine developed a tractive power of 8 tons, which is equal to the adhesion of the engine for a coefficient of friction of. This engine met the requirements of the Poti-Tiflis railway, but in order to reduce the dead weight still further, a 45-ton six-wheeled coupled engine is suggested as [1874-75. N.S.] Ꮓ sufficient for ordinary weather, the assistance of a second engine being employed when the state of the rails requires it. The Author adds some calculations as to the maximum gradient and minimum curve admissible on mountain railways, and also as to the number of carriages which should constitute a train in various cases. R. C. Description of some Narrow-Gauge Railways. (Annales des Mines, Nos. 2 & 3, 1874, 153 pp. 6 pl.) M. Ledoux investigated the details and specialities of narrowgauge railways in various countries, and has selected the following examples:-Line of Ergastiria in Greece, of Mokta-el-Hadid in Algeria, of Rochebelle, and of Cessous and Trébiau in the Gard. The eighteen smelting furnaces at the extremity of Ergastiria, on the eastern side of Laurium, a province of Attica, and about 7 miles from Cape Sunium, were established in 1864 for the treatment of ekbolades,' the slag of the ancients. To reduce the cost of transport M. Ledoux was entrusted with the construction of a narrow-gauge railway. The route was marked by the road, uniting Berzeko with the coast, which crosses the central chain of hills by the pass of Rotonde, 560-8 feet above datum. The starting point is 11-8 feet, and the terminal point 286-3 above datum. A maximum gradient of 1 in 28 was adopted between the works and the summit, for empty wagons only, and of 1 in 38 between the summit and Berzeko, for loaded wagons. The gauge chosen was that of Mokta-elHadid, 1 mètre between the inside edges of the rails. The first section had curves of a minimum radius of 197 feet, and the second of 230 feet. The principal dimensions of the rail are-height, 3.54 inches; width of top flange, 1.89 inch; thickness of web, 0.47 inch; width of bottom flange, 2.95 inches. The profile of the rail is adapted to fit the fish-plate. The inclination to the vertical of the line of contact is 125° 42'. It is moderately deep, the ratio of the depth to the half-width of the bottom plate being 2.4. For similar rails in actual use the value of this ratio is-Lyons, 2 and 2.6; Northern of France, 2.38; Eastern, 2.42; CologneMinden, 2.71. The fear, that in consequence of the sharp curves there would be a tendency to tilt the rail over on the outside edge of the bottom flange, has not been justified by experience. The exterior rails maintain their position, which proves that the width of the bottom flange is sufficient. The outward tendency has also been obviated by giving a great super-elevation, and a considerable inclination of the rails towards the centre of the road. The rails are of Bessemer steel, and they weigh 41 lbs. per lineal yard. They were manufactured at Bességes, and their cost was £9 38. per ton, delivered in trucks at that station. The following is a résumé of the total cost of the work : Excavation, including labour, powder, and plant, &c. Tunnel, including labour, powder, and plant, &c. Works of art Ballasting, labour and materials Permanent way, do. Level crossings, cottages, and fencing. Fixed materials, crossings, reservoirs, weighing machines Total. -: £. 3,954 3,136 1,584 903 7,838 134 807 1,624 19,980 The total length, inclusive of the sidings at Ergastiria, is 6 miles 2 furlongs 1 chain. The cost per mile of the main line was £3,354 (52,121 francs per kilomètre), as against £2,711 (42,135 francs per kilomètre), the amount per mile such a line would have cost in France. 20 The tank engines, made at the works of Messrs. André Koechlin & Co., at Mulhouse, at a cost of £1,250 each, were designed specially to suit the peculiarities of the line by M. Beugniot, the chief engineer of those works. The particulars of the boiler are as follow-proof pressure per square inch, 128 lbs. ; thickness of the plates, inch; number of the tubes, 125; internal diameter of the tubes, 13 inch; length of the tubes, 9 feet 7 inches; heating surface of the fire-box, 46.5 square feet; heating surface of the tubes, 487 square feet; total heating surface, 533 5 square feet; capacity of the boiler, 407 gallons. The fire-box is widened out towards the interior to give more grate area. There is a slope on the top of the fire-box from front to rear of 1 in 28, so that the top is level when the engine is descending the same gradient. This is done to avoid the risk of burning the top of the fire-box when the engine is about to descend, as happened once at Berzeko. There are two pumps, and one Giffard's injector. The tanks have a total capacity of 1,060 gallons. The boilers are able to generate steam very rapidly, owing principally to the great fire-box surface (more than one-twelfth of the whole), as well as to the short length of the tubes. The dimensions of the cylinders arediameter, 13 inches; length of stroke, 18 inches. The frame is composed of two side beams of plate iron 87 inches by inch. The overhang in the front is 6 feet 4 inches, in the rear 8 feet inch. The entire width of the frame is 7 feet 6 inches. The length between the buffers is 23 feet 9 inches. The centre of the boiler is 5 feet 1 inch above the rails, and the top of the chimney is 10 feet. The transverse beam in front is of cast iron, in the rear of wrought-iron plate. The axis of the traction bar is 2 feet 2 inches above the rails, and the working |