Read Ebook: Scientific American Supplement No. 530 February 27 1886 by Various

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The paper was illustrated with maps and diagrams.

THE MERSEY TUNNEL.

The description of the Liverpool lifts will well suffice also for the Birkenhead lifts. The former are under James Street, where above ground, rising in lofty stateliness, is a fine tower for the hydraulic power, the water being intended to be stored in a circular tank near its summit, the dimensions of which will be 15 feet in diameter and its internal depth 9 feet. From the level of the rails of the Mersey Railway to the bottom of this water-tank the vertical distance is 198 feet. At the western side of the subterranean railway there is, above the arrival platform, a "lower booking-hall," or, more properly, a large waiting room, 32 feet square and 29 feet high, the access to which on this side is by a broad flight of steps rising 12 feet, and to and from which all passengers on the departure platform have communication by a lattice bridge 16 feet above the line of rails. From the western side of this hall the passengers will have access to the three lifts, and will thence ascend in large ascending rooms or cages, capable of containing one hundred persons each, to the upper booking-hall on the ground level of James Street. Intermediate in height between the lower and upper halls the engine-room for the pumps is located. From the lower hall also there is provided, independent of the lifts, an inclined subway, leading up toward the Exchange. In this lower subterranean chamber there are four doorways, 5 feet wide, three of them being fitted with ticket gateways, and leading to the three lift-shafts, excavated in the rock, and lined, where needed, with brick. In each of these shafts, which are 21 feet by 19 feet in sectional area, a handsome ascending wood-paneled room, or cage, formed of teak and American oak, is fitted, its dimensions in plan being 20 feet by 17 feet, and its general internal height 8 feet; but in the central portion the roof rises into a flat lantern 10 feet high, the sides of which are lined with mirrors that reflect into the ascending-room the rays of a powerful gas-lamp. The foundation of this room is a very stiff structure, consisting of two wrought-iron special-form girders crossing beneath it, the cross, 14 inches deep, connecting them being of steel, and forged from a single ingot. The central boss of the cross is 22 inches in diameter, and in this is bored out a central cavity, into which the head of the steel ram, 18 inches in diameter, is fitted; the ram itself being built up of steel cylinders or tubes, 11 feet 3 inches in length, which are connected together by internal screws. There is also a central rod within the ram, as an additional security. The ram descends into a very strong cast-iron cylinder, 21 inches internal diameter, which is suspended in a boring 40 inches internal diameter, and carried down to a depth of over 100 feet in the rock. The two iron girders under the frame of the ascending-room or cage cross the entire lift space, and then at their outer ends are attached to four chains which rise over pulleys fixed about 12 feet above the floor of the upper booking-office. These chains thence descend to suspend two heavy counterweights, so arranged as to work in guides and to pass the ascending-room in the 12 inch interspace between the cage and the side walls of the shaft. These chains are of 1-1/8 inch bar iron, and have each been tested with a load of over 15 tons. The maximum load which can ever come as a strain upon any chain is about three tons. Two chains are attached to each counter-weight, and special attention has been paid to the attachments of these chains to the cage girders. The stroke of each hydraulic lift is 96 feet 7 inches. In the engine-room there are three marine boilers, each 6 feet 6 inches diameter and 11 feet 6 inches long, and three pairs of pumping engines of patented type, each capable of raising thirty thousand gallons of water per hour from the waste tanks below the engine-room to the top tank of the tower above ground. There are three suction and three delivery mains, and these are connected direct to the lifts by a series of change sluices, admirably, neatly, and handily arranged in the engine-room by Mr. Rich, and in such a way that any engine, any lift, or any supply main can be disconnected without interference with the rest of the system. When the tower tank is completed, it alone, under any circumstances, would be able to supply the lifts if every pumping engine were stopped. But if any or all the engines were working, they would automatically assist the top tank, for nominally they will keep the top tank exactly full, and will then stop of themselves. The tower, as we have indicated, is not yet completed, and the pumping engines are consequently doing all the work of the lifts. The ascent and descent of the cages is effected by the attendant who accompanies the passengers, by means of a rope arrangement.

Each cage or room is intended ordinarily to take a maximum freight of 100 passengers, calculated at about 15,000 lb. The hydraulic ram weighs about 11,000 lb., the iron frame and cross of the cage about 6,500 lb., and the cage itself about 13,200 lb., the total being about 30,700 lb. The mass in motion when a cage is fully loaded is estimated at 63,000 lb. dead weight. The journey of elevation will ordinarily be made within one minute, but in the experimental trials which have been made the full journey has actually been accomplished in 32 seconds. In the Board of Trade tests under General Hutchinson, weights to the extent of 15,000 lb. were variously shifted, and in certain cases concentrated in trying localities, but the cage stood the trials without any appreciable change of form, and in neither the cage nor the chains were any objectionable features developed. The three lifts can be worked singly or combined, so that the accommodation is always ready for from 100 to 300 persons. Further railway connections between the Mersey Subaqueous Railway and the surrounding land lines than those which yet exist are in contemplation.

All the booking-halls, waiting-rooms, etc., etc., in connection with the four stations have been laid with Lowe's patent wood-block flooring. The blocks are only 1-1/2 inches thick, but, being made of hard wood and securely fastened to the concrete bed with Lowe's patent preservative composition, they cannot become loose, and will wear for a long series of years, until, in fact, the wood is made too thin by incessant traffic.

The engineer, Mr. Fox, and the architect, Mr. Grayson, are much pleased with the work, especially as it is so noiseless and warm to the feet. These floors ought to be adopted more frequently by railway companies in connection with their station buildings, as "dry rot" and "dampness" are effectually prevented, and a durable and noiseless floor secured.

IMPROVED REVOLVER.

The Kynoch revolver, manufactured by the Kynoch Gun Factory, at Aston, Birmingham, is the invention of Mr. Henry Schlund. It may be regarded as the most simple in respect of lock mechanism of any existing revolver, whether single or double action. It extracts the cartridges automatically, and combines with this important feature strength and safety in the closing of the breech. Certainty of aim when firing is obtained by means of a double trigger, which serves many purposes. This secures quick repeating as in the double-action revolvers, and at the same time the revolver is not pulled out of the line of sight, as the trigger is pulled off by the forefinger, independently of the cocking motion, the cocking trigger being longer than the ordinary double-action triggers. The cocking trigger further serves to tighten the grasp, and so enables the power of the first recoil, which affects the shooting of all revolvers, to be held in check. The light pull-off enables a steady shooter to make surpassingly fine diagrams.

The upper side of the barrel is perfectly free from obstruction, so that the sighting can be done with the greatest ease, and the entire weapon is flush and without projections which can catch surrounding objects, with the exception of the cocking trigger, which seems to require a second guard to render it secure when thrusting the pistol hastily into a holster. At the same time, it should be remembered that the cocking trigger does not effect the firing. It puts the hammer to full cock and rotates the cylinder, and these operations may be performed time after time with safety.

MOTORS FOR STREET RAILWAYS.

RESULTS OF EXPERIMENTS ON MECHANICAL MOTORS FOR TRAMWAYS MADE BY THE JURY ON RAILWAY APPLIANCES AT THE ANTWERP EXHIBITION.

An interesting feature of the International Exhibition at Antwerp was the competition which was invited between different forms of mechanical motors on tramways for use in towns, and between different forms of engines for use on light railways in country districts, or as these are termed, "Chemins de Fer Vicinaux."

These latter have obtained a considerable development in Belgium, Italy, and other Continental states; and are found to be most valuable as a means of cheapening the cost of transit in thinly peopled districts. But owing to the fact that the Board of Trade regulations in this country have not recognized a different standard of construction for this class of railway from that adopted on main lines, there has been no opportunity for the construction of such lines in England.

There has, however, been a great development of tramway lines in England, which in populous districts supply a want which railways never could fully respond to; and although hitherto mechanical traction has not attained any very considerable extension, it is quite evident that if tramways are to fullfil their object satisfactorily, it must be by means of mechanical traction.

It is also certain that the mechanical motor which shall be found to be most universally adaptable, that is to say, most pliant in accommodating itself to the various lines and to the varying work of the traffic, will be the form of motor which will eventually carry the day.

The competition between different forms of motors at the Antwerp Exhibition, which was carefully superintended, and which was arranged to be carried on for a reasonable time, so as to enable the qualities and defects of the different motors to be ascertained, affords a starting point from which it will be possible to carry on future investigations.

I have, therefore, thought it advantageous to the interests of the community in this country to bring the results arrived at before this Society; and as the "Chemins de Fer Vicinaux," to which one part of the competition was devoted, have no counterpart in this country, it is proposed to limit the present paper to an account of the experiments made on the motors for tramways.

Certain conditions were laid down in the programme published at the opening of the Exhibition, to regulate the competition, in order that the competitors might understand the points which would be taken into account by the judges in awarding the prizes.

The experiments were made upon a line of tramway laid down for the purpose in the city of Antwerp, carried along the boulevards from near the main entrance of the exhibition to the vicinity of the principal railway station, a distance of 2,292 meters.

The line ended in a triangle of 505 meters, in order that those motors which required to run always in the same direction should be enabled to do so.

Out of the whole length of the line, viz., 2,797 meters, 2,295 meters were in a straight line, 189 meters in curves of 1 3/4 chains radius, and 313 meters in curves of 1 chain radius. There were on the line four passing places, besides a passing place at the terminus; these were joined to the main line by curves of 1 3/4 chains radius.

The line was practically level, the steepest incline being 1 in 1,000; this circumstance is somewhat to be regretted, but the city of Antwerp afforded no convenient locality where a line with steep gradients could have been obtained. The motors were kept in sheds close to the commencement of the line of tramway near the exhibition, where all necessary cleaning and such minor repairs as were required could take place.

A regular service was established, according to a fixed time-table, to which each motor was required to conform. Each journey was reckoned as starting from the end near the exhibition, proceeding to the beginning of the triangle, and returning to the starting point. An hour was allowed between the commencement of each journey, fourteen minutes were allowed for a stoppage at the end near the exhibition, and eighteen minutes at the other end--thus allowing twenty-eight minutes for traveling 2 miles 1,500 yards, or a traveling speed of about 6 miles an hour. The motors were required to work four days out of six, and on one of the four days to draw a supplementary carriage.

An official, assisted by a storekeeper, was appointed to keep a detailed record--

The experiments lasted about four months. Five competitors offered themselves, which may be classed as follows: Three were propelled by the direct action of steam, and two were propelled by stored-up force supplied from fixed engines.

It is somewhat to be regretted in the public interest that other forms of mechanical motors, such as the Mekarski compressed-air engine, or the engine worked with superheated water, or cable tramways, or electrical tramways, were not also presented for competition.

The Wilkinson engine had a vertical boiler and machinery. The cylinders were on the opposite side of the boiler from the door of the fire box, and mounted independently; the motion of the piston was communicated by means of a crank shaft and toothed wheels to the driving axle. The wheels were coupled. A regulator, injector, and a hand-brake were placed at each end, so that the engine driver could always stand in the front, whichever was the direction in which the engine moved; and there was a platform of communication between the two ends, carried along one side of the boiler.

The boiler was constructed with "Field" tubes, the horizontal tube plate having a flue in the middle which carried the heated gases into the chimney.

The visible escape of the steam is prevented by superheating. To effect this, the steam, as it leaves the cylinder, passes into a cast iron chamber adjacent to the boiler, which is intended to retain the water carried off with the steam. From thence the steam passes into a second chamber, suspended at a small height above the grate in the axis of the boiler and of the flue which conveys the heated gases into the chimney, and thence into a sort of pocket inclosed in the last-mentioned chamber, which is open at the bottom, and the upper part of which terminates in a tube passing into the open air. This method of dissipating the steam avoids the necessity of a condenser; but if it be admitted that the steam in escaping has a minimum temperature of 572? Fahr., it will carry away 12 per cent. more caloric than would have been required to raise it to a pressure of 150 lb. per square inch.

The steam escaping through the safety valve is passed through the same apparatus.

The toothed wheel on the driving axle is arranged to act upon another toothed wheel on a shaft connected with the regulator, so as to control its speed automatically.

The length of the engine is 10 ft. 10 in., its width 5 ft. 9 in., and the distance from center to center of the wheels 5 ft. 2 in.

The Rowan tram-car consists of a body 31 feet long and 7 feet wide, resting on a two-wheeled bogie behind and on a four-wheeled bogie in front, this front bogie being the motor, and the whole has the appearance of a long railway carriage, somewhat in the form of an omnibus with a platform at each end, of which the front platform is occupied by the engine. It requires, therefore, either a turntable or a triangle at the end of the line, so as to enable it to reverse its direction.

This motor is a steam engine of light and simple form, supplied with steam from a water tube boiler with very perfect combustion, so that no smoke escapes. The boiler is somewhat on the principle of a Shand and Mason boiler; it is so built that It can easily be opened and every part of the interior examined and cleaned.

The peculiarity of the Rowan motor is the simplicity of the attachment of the engine to the carriage, and the facility with which it can be detached when required for cleaning or repair, viz., in five or six minutes.

The steam can be got up in the engine with great rapidity if a change of engine is required. When, however, the engine is detached, the carriage loses its support in front, and is therefore not serviceable. When necessary, the combined motor can draw a second ordinary carriage.

The motor by itself occupies a length of 9 ft. 8 in. It has two horizontal cylinders; the four wheels of the bogie are coupled, and between the wheels the sides of the framing are rounded to allow two vertical boilers to stand. These boilers have vertical tubes for the water, which are joined together at the top by a horizontal cylinder. Each boiler, with its covering, is 1 ft. 9 in. in diameter. The boilers stand 1 ft. 9 in. apart, thus affording space between them for the motive machinery, including the pump. The crank axle is behind the boilers. The levers, the injector, the access to the fire-box, a pedal for working the engine brake as well as a screw brake for the carriage, are all in front. The brakes act on all six wheels, are worked by the driver, and the whole weight of the engine, car, and passengers being carried on these wheels, the car can be stopped almost instantaneously; and as over two-thirds of the entire weight of the car and passengers rests on the four driving wheels; there is always sufficient adhesion on all reasonable inclines, and the adhesion is augmented as the number of passengers carried increases. Hence this car is adapted for lines with heavy grades.

A small water tank is attached to the framing; two small boxes for coal or coke, with a cubic capacity of about 3 1/2 feet, are attached to the plate in front of the bogie. The covering of the boilers is in two parts, which are put on from each side horizontally, and screwed together in the center. The removal of the upper part enables the tubes to be examined and cleaned. The draught is natural; the base of the chimney is 3 ft. 2 in, from the grate; the height of the chimney is 5 ft. 2 in.

The steam from the cylinders passes directly into a condenser placed on the top of the carriage. The condenser is made of corrigated copper sheets millimeter thick. Two sheets, about 15 to 18 inches wide and 15 feet long, are laid together and firmly soldered, forming a chamber. Twenty of these chambers are placed side by side on the top of the carriage, connected with a tube at each end, so as to allow the steam to pass freely through them. The lower corrugations in the several chambers are connected together, and thence a pipe with a siphon to stop the steam is carried to a water tank under the carriage, which thus receives the condensed water. This arrangement afforded a condensing surface of about 800 square feet. It should be mentioned that with larger engines Mr. Rowan employs as much as 1,600 feet of condensing surface. The nearness of the chambers to each other tends no doubt to diminish the power of condensing the steam, but this is somewhat compensated by the artificial circulation of air produced by the movement of the carriage. But in any case, if there is surplus steam, the pipe from the condenser causes it to pass under the grate, whence it rises superheated and invisible through the fire and up the chimney.

Under the carriage attached to the framing are four reservoirs, holding about three and a half cubic feet of water, of which water space one-half acts as a reservoir for cold feed water, and half for the condensed water. A tube from the small reservoir on the engine communicates through valves with the reservoirs of hot and cold water on the carriage.

The consumption of cold water measured during two days was 2.86 lb. per kilometer; assuming that the boiler evaporated 6.5 lb. of water per pound of coal, the cold water formed one-fifth of the total feed water required.

The carriage, i. e., the part occupied by passengers, is 21 ft. 8 in. in length. It holds seats for forty-five passengers, besides those who would stand on the gangway and platform. The seats are placed transversely on each side of a central corridor, each seat holding two people. The platform of the carriage is about 2 ft. 6 in. above the rails. Passengers have access to the interior from behind by means of the end platform, and in front near the engine from the two sides. As already mentioned, the hind part of the carriage rests upon two wheels, the front part being, as already mentioned, supported on the engine bogie. To effect this support, the hinder part of the framing of the engine is formed in a half circle, with a broad groove, in which the ends of two springs are arranged to slide. The centers of the springs form the support of the framing of the carriage.

The framing of the engine bogie is attached to the hind bogie truck of the carriage by two diagonal drawbars. The coupling is effected by bolts close to the engine, and the car is drawn entirely by means of the bogie pin of the hind bogie. The trucks are 16.5 ft. apart.

The Beaumont engine, worked by compressed air, may be generally said to be similar to that described in a paper read before the Society of Arts on the 16th March, 1881, to which, however, some improvements have been since introduced.

The apparatus for compressing the air was placed in the shed. The air was compressed to 63 atmospheres by a pump worked by a steam engine, and stored in cylindrical reservoirs of wrought iron without rivets. A pipe led the air from the reservoirs to the head of the tramway, where the cylinder placed on the motor for storing the air during the journey could be conveniently charged.

The air was compressed by means of four pumps, placed two and two in a water-box, and worked by the direct action of a compound engine, with cylinders, placed in juxtaposition, of 8 in. and 14 in. diameter respectively, with an equal length of stroke of 13 in.

Krauss. Wilkinson. Rowan. Diameter of cylinder.........d 5.5 in. 6.5 in. 5.1 in. Length of stroke.............l 11.8 in. 9 in. 9.8 in. Diameter of wheels...........D 31.5 in. 27.5 in. 29.5 in. Pressure at which boiler is worked...........P 220 lb. 147 lb. 191 lb. l)/.............E 1,210 lb. 1,509 lb. 805 lb. Total heating surface........S 105 sq. ft. 105 sq. ft. 64 sq. ft. Grate surface................G 2.7 sq. ft. 5.4 sq. ft. 3.1 sq. ft. Surface of condenser.........C 274.482 s. ft. None. 861.120 s. ft. Weight in running order ...............P' 15,400 lb. 15,400 lb. 9,020 lb. Weight in running order ....................P" - - 15,400 lb. Contents of water tank.......- 28.24 cub. ft. 13 cub. ft. 4.2 cub. ft. Contents of coal bunks.......- 14.12 cub. ft. 12.5 cub. ft. 8.5 cub. ft. P'/E 12.7 lb. 10.2 lb. 11.2 lb. P"/E - - 19.125 lb. P'/S 146 147 140 P'/G 5,722 2,855 2,889 C/S 2.6 - 13.4 C/G 102 - 275

The air, after being forced through the first pump cylinder, passed successively through the other three, the diameters of which were of proportionately decreasing sizes, viz., 8.2 in., 5 in., 3.5 in., and 2 in., and the air on leaving each cylinder passed on its way to the next cylinder through a coiled pipe immersed in flowing water to remove the heat generated. This cooling surface amounted to nearly 54 sq. ft.

The cooling of the air was very efficient. In an experiment made on this question, the temperature of the compressor did not vary to the extent of 9? F. in charging the reservoir from 40 to 63 atmospheres, occupying an hour and a half, the consumption of water during the time being about 1,400 gallons.

The fixed reservoirs were of about 240 cubic feet capacity.

The motor formed part of a compound vehicle, which may be said to have consisted of two parts joined together by an articulated corridor, the whole being covered by a roof which was approached from the platform behind by an easy staircase. On this roof were seats for outside passengers.

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