The separate sections, constructed of the rails shown in Figs. 3, 4, and 5, are 1.5 metres in length; those built of the rail shown in Fig. 6 are 2 metres in length. The sleepers used on the Dolberg portable railway are preferably of creosoted pine. It is considered by the inventors that wooden sleepers are more advantageous than iron in the construction of temporary railways where the ground is frequently soft and yielding, owing to the greater surface they present. FIG. 16. light, and the method of operation so simple, that only one man is required at a time for laying down the rails. An average of twelve sections per minute has been reached on uneven ground; and it is claimed by the inventors that 1,000 metres may be laid per hour by employing relays of men. The hook joint, of course, obviates the necessity for using any form of screw or fish-plate. For more or less permanent railways and for field purposes when the country is level, Messrs. Dolberg advocate the use of somewhat longer sections, varying between 3 and 5 metres. The Dolberg portable railways include two systems of points or crossings-the automatic safety and the inclined plane points. For the former (Fig. 11) it is claimed that the derailment which frequently occurs at ordinary crossings is impossible; and the construction is so simple that repairs are rarely necessary. A car on the track A A (Fig. 11) approaching in the direction indicated by the arrow, would press the lever h1 towards the left, The attachment of rail and sleeper is simple and thereby moving the second lever h111, the connecting rod efficacious. The rails rest in a wrought-iron channel, so constructed that spreading or longitudinal displacement is impossible. Any tendency to shift in a longitudinal direction is obviated by means of a bolt or screw passing completely through the foot of the rail, the wrought-iron channel and the sleeper. This form of joint is shown in Fig. 7. The screw a passes through the entire thickness of the sleeper; while similar screws b running laterally, prevent any chance of splitting. The wrought-iron channels have the further advantage that they allow the railway to be constructed with a FIG. 17. FIG. 18. zz, and the sleeper ss, in such a manner, that the rails ab, al bl form the continuation of the track A A, and allow the car to run over the metals C C. 2 The inclined plane is exceptionally well adapted for temporary field purposes. In its simplest form (Fig. 12), the plane E, E, E, E, lies with its sharplypointed tongues E, E, on the main track A B, and the branch line C. The tongues form the plane over which the truck ascends from the main track on to the points. As may be seen from the drawing, this form of turn-off may be fixed in a few seconds to any portion of the railway. By this method a temporary passing-place may be formed when two trains meet on a single line, slight curve without the employment of specially pre- by providing the trucks of either train with a reserve pared sections. Fig. 8 shows a modification of the system, by which each section consists of a sleeper s and an iron cross-bar 2. The sleeper serves as a support for the cross-bar of the next section. For railways in which extreme rapidity of construction is desirable, Messrs. Dolberg have patented a special hook joint, shown in Figs. 9 and 10. Each section is so VOL. VIII. section apiece. Only one inclined plane is necessary for this purpose, for after it has been used to run the train on to the passing-place, it may be taken up and employed for the return to the main line. In some cases, when the rolling stock is light, as for instance in the system under description, it would not be necessary to construct a passing-place when an empty and a laden train approach one another. The empty trucks R would simply be tilted off the line, and replaced when difficulty is usually met in filling in the gaps. The the freight train has passed. For more or less permanent military railroads, Messrs. Dolberg have patented an inclined plane turn ordinary section never quite fits the interval, and much valuable time is lost in attempts to make good the deficiency. The difficulty is met in the Dolberg system off, which does not require removal for the passage of a train on the main track. The bent plates b1, b2 are placed, as shown in Fig. 13 on the rails 1 and 2 of the per t FIG. 20. manent way. The tongues of the turn-off are provided with sharp ends, hollowed out on the under side to grip the rails when the system is in use. When traffic is by the employment of the apparatus shown in Fig. 14. It consists of a framework R of angle iron, of which the opposite sides w fill the gap between the rails. In this manner a junction may be effected between two wholly different systems of railway, provided only that they have the same breadth of gauge. The bogie shown in Fig. 15 has been designed by the inventors of the Dolberg railway to meet the requirements of all-round military transport. It is constructed to receive almost any description of superstructure, and for use either independently or in combination with other wagons. By affixing a suitable box, the bogie may be transformed into a tipping wagon; or two of these frameworks may be employed to support a platform P, as shown in Fig. 16. By the latter arrangement, as much material may be carried as by four ordinary wagons on a bad road. For the trans resumed on the main line, the tongues are detached port of unpressed hay, or other bulky material, the from the metals and the flap r pushed back. In extremely rapid construction, when the railway is laid down at several places simultaneously, considerable platform sketched in Fig. 17 is best adapted. When used for the carriage of railway material, it is calculated that 120 sections could be packed one above the other with entire safety. This would represent, with sleepers of two metres in length, about 240 metres (260 yards) of railway, so that eight trucks of this kind would be more than sufficient for the transport of one mile of rails and sleepers. When the haulage is done by horses, it is found that a pair is able to draw from three to five wagons. In this case a strong brake is necessary. Messrs. Dolberg have invented an exceedingly effective automatic apparatus, in which the brake is applied to each wagon by the mere pressure of the trucks behind. The pull of the horse on the level or up hill immediately disengages two metres in length, composed of two rails and two sleepers. The section is so constructed, that at one extremity the rails extend 4 cm. beyond the sleeper, while at the other the sleeper projects the same distance beyond the rails. This space serves as a support for the next section. The construction of the railway is said to be so simple and rapid that two men, with the aid of a pair of horses, can lay down or take up 3,000 metres (nearly two miles) per diem. By employing a sufficient number of men, it is claimed that 1,000 metres could be laid down per hour. The method of fixing the rails, shown in Figs. 19 and the brake, while on steep declines the animal is in no danger of being injured by the impetus of the train. For war purposes, the possibility of placing large transport wagons on the railway as shown in Fig. 18 is of extreme importance. Two small four-wheeled bogies and a carriage landing are the only requisites for mounting the wagons. For field use, the inventors of the Dolberg railway employ a portable carriage-landing consisting of two wooden platforms, the extremities of which form an inclined plane. The wagon is run up the incline on to the platforms, between which lies the track with the two bogies. The latter are specially fitted to receive the axle-trees of the wagon. It is estimated that 500 metres of railway on the Dolberg system, with a gauge of 70 cm. and rails of 55 mm. in height (46 kg. per metre), would weigh about 8,000 kg. and cost £75. This is at the rate of £240 per mile. The cost of 35 wagons for the same distance would be about £400. Assuming that an army corps would require 150 miles of railway, the total cost, including rolling stock, would amount to about £96,000. The Spalding System. Herr Spalding claims for his railway that it may be laid down on the most uneven ground, and opened for traffic without any planishing of the soil. This result is only to be obtained by the use of short sections, and a carefully-devised joint. While Décauville employs sections of five metres in length, consisting of several sleepers, Spalding makes use of a section only 20 is designed to prevent shifting in any direction. The necessary rigidity is obtained by means of a toughened cast-iron ground-plate, which is let into the wooden sleeper by a groove b, and is firmly connected with the rail by means of a bolt a. The rail itself is secured to the sleeper by two clips passing over its lower flange. The groove b prevents any lateral, the bolt a any longitudinal movement of the rail. In this connection it is noteworthy that the rails may be detached from the sleeper by partially unscrewing the clips. This is of consider FIG. 23. able importance in transport, as the sections may be taken to pieces for packing, and thus occupy a minimum of space. For field purposes, Herr Spalding has invented two types of points, an automatic turn-off, and an automatic inclined plane. The former (Fig. 21) consists of two principal parts A and B. The double tongue moves in such a way that either c or d effect the junction with the rail e. The title "automatic" is derived from the fact that the tongues c and d are pushed into position by the engine wheel, and that by means of a spring one of the two tongues is always in contact with e. There is, therefore, no chance of derailment, and the apparatus is stated to be absolutely dirt-proof. The automatic inclined plane (Fig. 22) consists of the straight rails 1 and 2, superposed on the main track, the curved rails 3 and 4, and the parts 5 and 6 similar to those employed in the construction of the automatic turn-off. The rails are supported by the sleepers S1, S2, S3, and, when the points are in use, lie directly over the sleepers of the main track. The tongues P1, P1, sharp at the point, and hollow on the underside, are constructed on hinges to allow of a slight turning movement around the rails 1, 2, and the parts 5, 6. At the crossing k, the wheels of the trucks run on their flanges. Herr Spalding has adopted for his system a gauge of 60 cm. (about 2 feet), which he considers the most serviceable for temporary field purposes. A broader A broader gauge involves the use of a comparatively heavy rolling stock; while a narrower one enormously increases The weight of each section of the railway is 75 lbs. ; and the rails, 5 feet 6 inches long between the supports, are able to bear a load of 4,400 lbs. The cost of Spalding's railway does not materially differ from that of Dolberg's system. The Haarmann System. Herr Haarmann, in common with the inventors of all other portable railways, claims for his system the advantages of extreme lightness and portability combined with great stability, a simple and effective rail-joint and adaptability to inequalities of ground. The rails used in the construction of the Haarmann section are constructed on the Vignole system, in three sizes, weighing respectively 4, 5, 8, and 75 kilogrammes per metre (8, 116, and 15 lbs. per yard). The corresponding sleepers, which are of steel, weigh 3, 4, and 9 kilogrammes respectively per metre (6, 8, and 18 lbs. per yard). The rails are joined to the sleepers by means of nuts and bolts, or by holdfast screws. the number of wagons and trucks, owing to the limited carrying power of each. Both for permanent way and rolling stock, the inventor advocates the use of wood wherever this is possible. It is, he contends, at once more elastic, more durable, and more easily repaired than iron or steel. An injury to a wooden wagon or sleeper may be remedied on the spot; whereas iron and steel fittings can only be repaired in the factory. Herr Landrath a D. Schulbarth, in commenting on the value of Spalding's system, observes that, whereas Décauville provides his employés with two large trucks of tools and reserve matériel, Spalding only provides a key for locking the screws. Spalding's wagon, specially constructed for the portable railway, is shown in Fig. 23. The wooden frame of the truck rests upon gutta-percha supports, and the wheels are doubly flanged. A powerful brake is provided, capable of being used from either side of the wagon. FIG. 25. For railways in which extreme portability is required, the sections of this system are constructed in lengths of 2 metres, weighing 35 kilogrammes (77 lbs), and capable, therefore, of being carried by one man. The rail-joint does not differ widely from that of Décauville It consists of two projecting tongues by which the stem of the next rail is gripped; but the plate underneath the rail, upon which Décauville relies for support and solidity, is here dispensed with. An alternative method is to provide the projecting tongues with a cross-bar which engages in a hook-shaped aperture in the body of the next rail. The rails are laid down, as shown in Fig. 24, by the aid of a bogie. No other apparatus is required. For railways of a more permanent type, sections. 5 metres long, weighing 80 kilogrammes (176 lbs.) are constructed. These necessarily require two men for transport and fixing (Fig. 25). A special form of section is supplied when a curve is required. Eight of these are sufficient for a curve of 90 degrees. (To be continued.) D A NEW AMERICAN PROJECTILE. YNAMITE has recently been the subject of numerous experiments in both Europe and America, and this explosive will undoubtedly have a high place among the necessary materials for carrying on the wars of the future. Mr. J. McCreary of Webberside, Mich., fully convinced of the great value of high explosives for military purposes, has been experimenting with THE MCCREARY DYNAMITE SHELL. dynamite, and our diagram shows a new system of construction for shells which the inventor has recently patented, embodying principles interesting to gunners in every part of the world. The shell or cylindrical part of the projectile is made of steel, and is attached to the head by rivets or screws. The head has a central opening through which the firing pin extends, and which is held in position by means of a pin near the point of the head, as shown. The firing-pin passes down through a perforated tube of pasteboard, and, at its lower end, which is reduced in size, is a percussion cap. Around the whole length of the central perforated pasteboard tube is a layer of coarse gunpowder enclosed in sheets of tissue paper. The main part of the interior of the shell is filled with dynamite which is kept from contact with the gunpowder and the firing-pin by the tissue paper. The inventor claims that a shell made after this system is safe to handle, there being no danger of a premature explosion, as is the case with shells that are exploded by means of electric apparatus or clock work. The firing-pin being held in place by means of a small rivet case, explodes only at the time the shell strikes, which is the best time to inflict the maximum damage on forts or armoured ships. Since the cap of the firingpin is exploded by striking against the bottom of the shell, and the gunpowder ignited first at that point, the dynamite is so fired that almost all its force is directed forward, and thus its destructive powers are considerably increased. By the use of dynamite of compara tively low power, (so as to render it safe for light field-artillery) a few batteries of guns could make woods more dangerous than an open plain, for any shell that could be fired from a 6-lb. field-piece would be suffi ciently large to tear the top of a large tree into fragments, and rout out everybody in the vicinity. This projectile can be made of large or small size, so that it can be fired from guns of any calibre with safety. The inventor claims that even with dynamite of low power, no armoured vessel in the world could withstand the destructive effects of one of these shells fired from any of the large guns in common use. |