Collected by Joe Thompson
The Cable Street-Railway
|The Difficulties of Making a Cable Trench.
(View of underground work at Broadway and Fourteenth Street, New York.)
|A Forty-two Ton Cable Spool on its Way to the Power-house (22k image).|
The chief reason why New York, aside from the difficulties of obtaining the necessary permits from the city authorities, was so far behind other cities in replacing horse - car lines by cable roads, was that here the cost of laying the cable was much more than in smaller cities. The expense of cutting a path through the net-work of pipes of every description in the New York streets frightened capital away. The illustration showing the work of laying the cable-trench at Broadway and Fourteenth Street gives some idea of the difficulties which had to be overcome. Here were no less than thirty-two different pipes belonging to more than a dozen different companies -- gas, water, sewer, steam, pneumatic, electric, etc. All these companies had rights which the cable company was under bonds to respect. The work of getting the pipes out of the way had to be done without interfering with the service of each of these corporations. Sometimes days were wasted in trying to find the owners of pipes that had been abandoned, perhaps for years. Gas companies and steam companies had gone out of business, but had left their pipes to make the confusion under the pavements worse confounded. The enormous cost of this work explains the high price asked by some of the contractors for certain parts of the lines in New York City. Some blocks along the lower part of the Bowery are said to have cost the contractors at the rate of $300,000 a mile.
The construction of the cable trench is simple enough, and may be plainly seen from the accompanying illustration. It consists virtually in a sectional iron tube, with a slot open at the surface of the street. In the tube are the wheels or sheaves upon which runs the cable. At intervals of thirty-one feet are openings by means of which the workmen may get at the sheaves for purposes of oiling and observation. The castings used in keeping the cable tube in place also support the rails upon which the cars run. In a street not already filled up with pipes, this work would be easy. In crowded parts of New York, it was disheartening, and one contractor threw up his contract in despair.
|Cross-section of the Road-bed of a Cable Railway. (12k image - no thumbnail)|
The most interesting part of the cable system to a layman is unquestionably the power-houses containing the machinery which moves the cable. In principle this machinery is simple enough, consisting of a steam engine which turns the drum or series of drums around which the cable passes. In practice the apparatus is more complex. Taking one of the most simple of the driving plants, that in the power-house of the Broadway road, at Sixth Avenue and Fiftieth Street, the piston of the 1,000 horse-power Corliss engine turns a big fly-wheel weighing 56 tons, measuring 24 feet in diameter and revolving at the rate of 66 revolutions a minute. Geared upon the same shaft with this fly-wheel is a drum 14 feet in diameter connected by cotton cables with another drum 32 feet in diameter. Geared on the same shaft with this big drum is a pair of 12-foot wheels, around which the street cable passes and from which it gets its power. The 2-inch cotton cables connecting the engine-shaft drum with the big driving-shaft drum are known as Lambeth cables, and were first made in England for some cable plants established in Australia, where more than a dozen (! - JT) cities are now supplied with such street railways. As yet we have to import these cables from England, and the four men in this country who understand how to splice such cables are in the employ of the English manufacturers and are kept busy travelling from city to city making the necessary splices. These are necessary when the cotton cables stretch too much. These big cotton cables, which when in use look very much like wire, are thought by most people who have seen illustrations of the cable machinery to be part of the cable which runs in the street. In reality, they simply take the place of the leather belts used in ordinary machinery to communicate power from one wheel to another. Upon some of the drums twelve or fifteen or even thirty cables are used. Upon the largest drums in this country, those in the power-house in the basement of the building at Broadway and Houston Street, the big drums are 32 feet in diameter, with a face 5 feet 4 inches wide, and carry 30 cables. Some idea of the enormous size of the largest of these drums may be obtained from the illustration showing the inside surface of one of these gigantic wheels, weighing 106 tons. After passing around the driving drums, the cable, before starting on its long journey through the streets, is straightened out automatically, in order to keep its tension about the same all the time, notwithstanding the pull to which it may be subjected by the cars. In the illustration on the opposite page will be seen the device by which this is accomplished in the power-house at Fiftieth Street. The cable, as it leaves the driving drum, passes over a big wheel mounted upon a movable carriage; this carriage is attached to a wire cable at the other end of which is fastened a huge weight of several tons, so arranged as to rise and fall according to the pull upon the street cable. When comparatively a few cars are running along the cable it is apt to be slack, and this movable carriage takes in this slack of the cable by pulling it toward the tower in which the weight, seen in the illustration, moves up and down according to the pull upon the main cable. The Broadway and Third Avenue cable lines each have two power-houses. The engines at Fiftieth Street and Sixth Avenue run the Broadway cable from Fifty-ninth Street and Seventh Avenue down to Thirty - fifth Street; those in the building at Houston Street run the other sections from Thirty-fifth Street down to Houston Street, and from Houston Street down to the Battery. On the Third Avenue line the engines in the power-house at Sixty-fifth Street, the old horse-car stables, run the cable from Sixth Street to 130th Street. Those at Bayard Street, in the Bowery, continue the work to the City Hall terminus of the line. Thus the longest piece of cable in use in New York is that from Sixth Street up to 130th Street, a distance of about six and one-half miles, making 13 miles of cable. The weight of this wire rope is something like two hundred and sixty tons. It has been estimated that to move this cable slowly through the trench, without the weight of any cars, would require the combined strength of one thousand two hundred men. The cable is sent to New York from the Trenton Works wound upon gigantic spools which hold from forty to sixty tons of wire. The illustration shows a spool, weighing 42 tons, in transit from the boat to the power-house. Thirty horses were used in this instance, and though the wheels of the truck are immensely wide, they are apt to leave their mark on the paved roadway. The finest power-house in New York and the largest cable-plant in the country, is that of the Third Avenue line at Sixty - fifth Street. The engine-room measures 137 feet in width by 170 feet in depth; its glazed roof is 84 feet high. In handling the machinery, most of which is of extraordinary weight, a Sellers electric crane of 24 horse-power has been used; this crane consists of an immense double girder stretching across the engine-room and running upon tracks near the roof. Upon the girders themselves runs the lifting apparatus. Thus by this double movement, any object weighing less than thirty tons may be picked up, and carried to any part of the big room, as quickly and easily as a workman can carry a ten-pound casting. Both the motive power of the crane and its lifting power are electric. Four engines of the Providence-Corliss type, 40 inches diameter of cylinder and 72-inch stroke, one thousand horse-power, are used to propel the cable machinery. The flywheels are 23 feet in diameter and weigh 40 tons; the driving drums are 22 feet in diameter, connected with the 32-feet shaft-drums by 22 two-and-a-half-inch Lambeth cotton cables. The drums around which the street cable passes are 15 feet in diameter. The boiler-room of this fine plant faces on Second Avenue, and is one of the largest and best lighted in the country. It contains 32 horizontal tubular return boilers of 125 horse-power each. The coal used in each furnace is weighed automatically as it passes in, so that, at the end of the day, the engineer can tell by a glance at the dials what each boiler has consumed.
|Under Side of a Great Drum at Houston Street and Broadway.
Diameter, 32 feet; weight, 106 tons; face of wheel, 5 feet 4 inches, carrying 30 cotton cables.
|The big Drums at Third Avenue and Sixty-fifth Street. Driving Wheel and
Street Cable in foreground.
|Tower and Weight for Keeping the Cable Taut.
(Fiftieth Street and Sixth Avenue.)
The power-house at Houston Street and Broadway offers no such picture of comfort and convenience as that at Third Avenue, for it is crowded with machinery, and so dark that electric lights have to be used everywhere, even at noon. In the construction of this power-house great ingenuity was displayed by Major G. W. McNulty, the engineer in charge of the line. The problem was to provide sufficient room for the gigantic machinery used, and yet get some income out of the property, which at this point is valuable for renting purposes. The excavations upon the plot, 100 feet wide on Broadway by 200 feet on Houston Street, were carried to a very unusual depth, 40 feet below the level of the street. It was considered necessary, if the building was to be used for business and office purposes, that the vibrations of the machinery should be felt as little as possible, and with this end in view the whole plant of the cable road stands upon its own foundations, while the iron pillars and stone piers which support the building above, are independent of the floors which contain the machinery. The plant at Houston Street varies but little from that in the other stations, and consists of four engines of the Corliss type, 1,000 horse - power, geared to a series of drums. The gearing is more complicated and expensive than at Fiftieth Street, or over at Third Avenue, owing to the cramped space. As compared to the other power-houses, the engineers employed here have rather a hard time of it, owing to the darkness and the heat. Last summer, before all the steam-pipes were properly jacketed with non-conducting material, the heat in the engine-room often rose to 120 degrees F.
The cable used in New York is similar to that employed all over the country. Upon its perfection and durability largely depends the successful working of the road. The grip by which the cars are made fast to the cable is the same upon both lines. This famous grip is the source of constant wonder to the public, and yet it is extremely simple, consisting virtually of a clamp two feet long through which the cable passes. The upper part of the clamp is raised or depressed by the brake under the driver's hand. When depressed, it grips the cable more or less firmly; if not very tight, it allows the cable to slip somewhat, thus carrying the car along at a slow speed. When tight enough to allow no slipping, the car of course moves along at the same speed as the cable, which in New York is about eight miles an hour in the upper parts of the city, and six miles down town. It might be thought that the friction and wear of this system would be destructive to the cables, and it unquestionably does shorten their lives. But the steel cable is of extraordinary strength and endures the constant clamping of these grips a thousand times every day without showing much wear. The first Broadway cable lasted six months, and it had to stand all the hard usage of inexperienced hands when the gripmen were new to the business. The accidents which at one time made New Yorkers rather nervous as to cable - cars on Broadway, were due to the unravelling of cable strands worn out by the friction of the grip. These strands twisted themselves around the grip, and it was found impossible to let the cable go. So upon one or two occasions the car went on at full speed, carrying everything before it and accumulating quite a collection of other cars and vehicles before a frantic telephone message to the powerhouse resulted in stopping the cable.
The cable-cars that run on the East River Bridge, between New York and Brooklyn, carry more people than any other cable road in the world, the average traffic last year exceeding 105,000 passengers a day, or about forty millions a year. Upon this bridge line the driving machinery is very similar to that of our street railways. The grip in use, designed by the late Colonel W. H. Paine, is upon a different principle, and consists of a group of wheels, against the periphery of which the cable rubs. The brake which stops the grip-wheels also forces them against the cable. This grip is said to be less severe upon the cable than the clamp-grip, but it is not so direct, and consequently so rapid, in its action, and rapidity is needed for the constant stoppings and startings of street-railway traffic.
|The Cable Grip (14k image).|
|Connection of Grip with Cable. (7k image - no thumbnail)|
A broken strand is the bugbear of the cable engineer. It is a costly as well as a dangerous affair. The piece of damaged cable has to be cut out and the ends spliced -- a delicate operation for which only a few skilled workmen in the employ of the cable manufacturers are competent. In order to guard so far as possible against this danger, the whole cable plant is virtually double -- engines and cable. One plant runs for twenty-four hours, when the other plant takes its place and allows the engineers an opportunity to give the plant which is resting a thorough examination. Besides this, a man is always stationed at the spot where the cable leaves the power-house; he keeps his eye on the cable and gives the signal to stop when he detects signs of anything wrong.
As it may be a matter of life and death to be able to stop the cable instantly, the driving drums in all the power-houses are held in place upon their shafts by friction-brakes which may be loosened in two seconds, thus stopping the cable though the engine continue at work. Were it not for this friction-brake, it would be necessary to stop the engines before the cable could be brought to a standstill, and with a 50-ton fly-wheel going at the rate of 60 or 70 revolutions a minute, such an operation requires time. Meanwhile a runaway car may be spreading havoc along Broadway.
One of the engineers of the cable road, in speaking of the accidents in which the cable-car takes the bit in its mouth, so to speak, and runs away, said that the public seemed apt to become much more frightened when this occurred than there was any reason for. Some people have an idea that when anything goes wrong with the cable, the car may suddenly begin moving at some terrific rate of speed, carrying everything before it until it dashes itself and its unfortunate passengers to pieces. Any one who takes the trouble to think about the matter, will realize that under no circumstances can the car go faster than the cable itself, or eight miles an hour. The passengers who remain in a run-away cable-car are perfectly safe -- except as they may be injured by flying glass and splinters when the car runs down other vehicles in its way. If, by any means, the car is brought to a standstill while the grip is still fast and the cable going, the whole grip apparatus would be torn from the bottom of the car; and this has been provided for.
A runaway cable-car is a far more dangerous affair to those who get in its way than to its own passengers. The most effective object-lesson in teaching one the tremendous power of the cable is to see the playful manner in which a heavy truck is thrown out of the way by the cable-car when the brakes fail to work quickly enough, or the driver of the truck fails to obey the cable-man's warning gong.
Within the last six months more than a score of devices designed to lessen the danger of running over people who may get in the way of a car have been offered to the cable companies. Not only is the speed more than that of horse-cars, but the force is a hundred-fold greater. That which appears to meet the approval of most experts is a species of guard or shield, almost touching the ground, or so near the pavement that it will push before it or out of the way any large object, thus acting as the cow-catcher of a locomotive. Several fatal accidents have made imperative the adoption of some adequate safety device.
|Longitudinal Section, showing Conduit, Sheave Pit, and Grip Hatch. (26k image).|
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Last updated 01-January-2014