This article, from The Street Railway Journal, February, 1897, describes the New York and Brooklyn Bridge Railway.
Among the many difficult transportation problems which have had to be solved in New York City and vicinity, few are more interesting than that of taking care of a traffic ranging from 40,000 to 225,000 passengers per day, and of 1000 to 20,000 passengers per hour, which is offered to the railway line 6000 ft. long which crosses Brooklyn Bridge. The best engineering ability and experience has been devoted to solving this problem and to providing an absolutely continuous, regular and safe service to the public, and when it is stated that during the last eight years the total amount of time lost on the railway by delays from all causes has been but 48 hours 43 min. equivalent to almost exactly one minute per day, or of one second for each 1800 passengers carried, and that during the thirteen years in which this line has been operated, over 435,000,000 passengers have been transported, with an accident account showing but two fatalities and one severe injury to persons on the trains, it will be seen how thoroughly results have justified the engineering decisions made, and how profitable will be a study of how this marvelous record has been achieved. It is particularly fitting, too, at this time when plans for increasing the capacity of the Bridge Railway which were originally made several years ago, have now been carried into effect (with various modifications) to briefly review the history of the bridge as a transportation feature of the Greater New York, and to explain with some care the system as it exists to-day with all its improvements.
The building of a bridge between New York and Brooklyn first took shape in 1867 as a private enterprise, but it almost immediately assumed a semi-municipal character, as the cities of New York and Brooklyn subscribed to about ninety per cent of the bridge company's capital stock and issued municipal bonds for the construction of the bridge. The control of the enterprise remained for some time, however, in the hands of the private stockholders, but their stock was eventually purchased by the city. On May 23, 1867, John A. Roebling was appointed Chief Engineer, and on Sept. 1, of the same year, he submitted his first general report outlining the plan of the bridge substantially as it now exists. Mr. Roebling's death occurring soon after this time, his son, Col. Washington A. Roebling, was appointed Chief Engineer, and it was under his supervision that the construction of the bridge was carried through to completion. Construction commenced Jan. 3, 1870, the bridge was opened for pedestrians and vehicles on May 24, 1883, and the Railway was opened to passengers on Sept. 24 following. The cost of the bridge itself at its completion, exclusive of land, was about $11,500,000, and the total cost to Apr. 1, 1884, was $15,552,878, this amount including land and land damages, buildings, interest during construction and miscellaneous items.
The bridge is so well known as one of the world's great structures that only the briefest description of its engineering features is here necessary. The main span, which is, at its highest point, 135 ft. above high water mark, is supported from two masonry towers founded on caissons, 168 ft. X 102 ft. and 172 ft. X 102 ft., respectively, each weighing about 15,000 tons complete. The length of the river span between the towers is 1595 ft. 6 ins., and of each land span 930 ft. The length of the Brooklyn Approach is 998 ft., and of the New York Approach 1552 ft. 6 ins. The total length of the bridge structure between the curbs of Center Street, New York, and Tillary Street, Brooklyn, is 7580 ft. The entire structure, with the exception of the caissons underlying the two piers was built by day's work instead of by contract; competent workmen in the several departments being employed under the constant supervision of the engineers in charge. The results have been interesting in a number of ways to the student of engineering methods. For example, the two roadways for vehicular traffic are comparatively narrow, and are subject to constant wear over their entire surface, sometimes from loads bearing eight tons on a single wheel; nevertheless, they are still in good condition after thirteen years of service, during which time there have been practically no repairs, while the city streets nearby on both sides of the river have been paved two or three times in the same length of time. The masonry of the bridge has been pronounced by competent engineers to be among the finest examples of good work in existence. After fifteen years of life it is as perfect (except in one place where a small crack has developed, and that of no consequence) as when first put up, while in one or two places where changes in design have made it necessary to take down portions of the structure, it has been found impossible to separate the stones without danger of fracture, except by chiseling away the mortar between them.
The floorings of the roadway at certain places where such construction could be used have given remarkable service and form one of the best examples of intelligent engineering to be found in any similar structure. They consist of a series of parallel longitudinal brick arches of 3 ft. 6 ins. span and 3 1/4 ins. rise, laid between 9 in. rolled iron beams. The arches are of a single course of brick 4 ins. thick and backed with concrete 1 3/4 ins. deep at the crown. Over this are granite paving blocks 7 ins. deep, laid upon a 1/2 in. layer of clean coarse sand, and the total depth from the spring of arch to the upper surface of the paving is but 16 1/2 ins. The under side of these arches is now as clean and free from cracks and leakage as when the masons removed the centers. A similar construction, but with brick arches 8 ins. in thickness, 4 ft. span and 6 1/2 ins. rise forms the flooring for the car storage yard in Brooklyn which covers an area 595 ft. X 105 ft. or about 1 3/4 acres. These arches are covered with a backing of concrete brought to a plane surface and then coated with asphalt, thus forming a smooth watertight floor upon which are laid the long wooden stringers held together by plate iron ties.
The traffic features of the bridge are three in number; two roadways for vehicular traffic, each 18 ft. 9 ins. in width run across the bridge, the north side taking Brooklyn to New York travel, and the south side New York to Brooklyn travel; next to these roadways toward the center are two spaces, each 12 ft. 8 ins. in width, given up to the bridge railway which is built with gradients greater than the roadways; and in the center of the bridge is a promenade 15 ft. 7 ins. wide, for pedestrians, which is between the two towers of the bridge elevated above both cable railways and roadways.
CONDITIONS OF TRAFFIC.
The relative increase of population of the cities of New York and Brooklyn is shown diagrammatically in Fig. 2 from which may be obtained some conception of the transportation problems which will confront the two cities thirty or forty years hence when 5,000,000 people may be expected to find a residence in the two cities.
In an interesting map prepared in 1888 by A. M. Wellington, it was shown that in an area swept by a radius two miles long from a center at the New York City Hall, 4.1 sq. miles of New York territory, and 0.9 sq. mile of Brooklyn territory was contained, the former having an assessed valuation of $132,000,000 per square mile, and the latter but $73,500,000 per square mile; while in an area swept by a radius nine miles long from the same center, 17.4 sq. miles of New York territory was contained and 62.1 sq. miles of Brooklyn territory, the former having an assessed valuation of $52,600,000 per square mile, and the latter $5.479,000 per square mile.
In 1867 the ferries between New York and Brooklyn, then the only means of transportation, carried 40,000,000 passengers across the East River; to-day, the traffic between Long Island and Manhattan Island can hardly amount to less than 100,000,000 passengers per annum, of which nearly or quite 45,000,000 cross the bridge.
It is not, however, by the consideration of the gross traffic offered to the Bridge Railway that an adequate idea of the difficulties of the transportation problem can be obtained, nor by the average daily traffic throughout the year, but rather by an understanding of the maxima at different hours of the day and on special days of heavy traffic -- moreover by the remembrance that provision of transportation facilities must be made, not for to-day nor yet to-morrow, but for twenty, thirty and even fifty years hence if waste investment is to be avoided. Consider, for example, the diagram of traffic in Fig. b on p 72. This engraving shows that during the last three years, when the traffic on other railroads has fallen off materially, that on the bridge has been well maintained. The normal annual growth during the years from 1886 to 1893 was about 3,000,000. It is not thought, however, by students of municipal growth that the future increase will be an equally high percentage, even if there should be no additional bridges. The growth of Brooklyn is largely on and along its easterly margins, and from this any increase in traffic over the Bridge Railway as well as over the Union Ferries (South, Wall, Fulton and Catherine Streets) must come, if it comes at all. Wellington's map, already referred to, shows that the trend of movement is towards upper New York, the lower portion, that part of Brooklyn reached by the Bridge and ferries, being saturated. Hence, since the crosstown railways in Brooklyn, electrically equipped, well and rapidly operated, deliver passengers at the foot of Broadway, from which they may speedily move to points above Union Square, New York, the overflow of traffic will be in that direction.
Fig. 6 shows the way in which the traffic varies from month to month, certain months having considerably more than others, and in Fig. 3 is shown an example of the way in which the traffic varies from hour to hour in a twenty-four hour day. Here we see that over 14,000 passengers must be taken care of in the hour from eight to nine o'clock in the morning and the same number of passengers from six to seven o'clock at night, and this at present by four-car trains having a total carrying capacity, sitting and standing, of 600 passengers.
OPERATION OF THE CABLE RAILWAY.
The Bridge was opened for foot passengers, May, 25, 1883, but the cable railway was not put in operation until Sept. 24, 1883. While similar to an ordinary cable railway in many particulars, the location on an elevated structure made possible the employment of certain features which were not ordinarily a part of a surface line and which have materially increased the efficiency of service and the life of different parts. The problems to be solved in the operation of the line were the regular transportation of a very much larger number of passengers than had ever before been attempted by a cable line, rendering necessary the use of more commodious and consequently heavier cars, the hauling of these cars over steep slopes, and terminal stops at elevated platforms, involving the necessity of perfect control over the car movement. That these conditions were successfully overcome is amply shown by the fact that during the history of the Bridge Railway up to Dec. 1, 1896, or for a period of 13 3/16 years, 435,150,309 passengers have been carried with unparalleled regularity and safety. During this period there have been but two accidents which have resulted in severe or fatal injury to a passenger.
When new the cables are 1 1/2 ins. in diameter and of an ultimate strength of over 114,000 lbs. The section of the cable is, of course, somewhat reduced by use, and when removed the diameter is about 1 5/16 ins. The following table gives the cable service on the bridge railway:
A large factor in the life of the cables has been the roller grip which was designed especially for this service. This grip holds the cable by means of two pairs of horizontal wheels having grooves lined with rubber and leather. The action of these grip wheels is supplemented by a pair of short solid rubber lined jaws which grasp the cable after the speed of the car has been brought up to that of the cable or nearly to it by the roller grip. Tests show, however, that the wheels without the solid grips have equal or greater traction than with them. In other words the solid grip attachment is practically unnecessary. The cable is lifted into place in the grip by external means. The pressure for holding the cable is transmitted to each grip wheel from the car platform by means of handwheel and rods through the medium of a wooden brake shoe applied to the inner surface of the rim which is flanged for this purpose. This brake shoe serves the double purpose of applying the pressure and checking the motion of the wheels until they cease to turn, when the car will travel at the same speed as the rope. The grip is attached to each car of the train. To further abate the wear on the cable the carrying sheaves are also packed with leather and sheet India rubber, so that the cable is in contact with iron only in the grooves of the winding drums.
The cars are fifty feet in length from center to center of drawbar and have four doors, one at each end and one at the middle of each side, for easy ingress and egress of passengers. They are fitted with two rows of longitudinal seats, one on each side. The cars weigh nineteen tons each.
The power station is located in Brooklyn close to the Brooklyn terminus. A plan of the driving machinery is given in Fig, 8. It is arranged so far as possible in duplicate, there being four sets of driving drums and four engines, one of 1000 h. p., one of 750 h. p., one of 500 h. p., and one of 250 h. p. The engines are directly connected by means of friction clutches to the main driving shaft, which is in several sections, or by gears. The shaft revolves at seventy revolutions per minute. Any or all of the engines can be cut out of connection with the shaft, so that any one may be used to operate the machinery alone. Generally for a considerable interval during a full day each engine is used, and during heavy loads two or more can be employed for furnishing necessary power, but so far they have not been required. Any set of driving drums can also be cut out if desired.
The driving drums are 12 ft. in diameter and are each fitted with four grooves for driving the cable. To provide for a possible unequal division of work between the two driving drums of a pair, power is not transmitted to them from the main shaft directly, but by means of a differential device illustrated in Fig. 7. The pinions which mesh into the driving drum gears are not keyed to the main shaft, but are mounted on sleeves. They are actuated by three small beveled gear wheels 120 degs. apart mounted on shafts, fast to the main shaft and radial to it. These beveled gear wheels mesh into the sides of the pinions driving the main drums. By this means one drum is at liberty to travel faster or slower than the other as the distribution of strains may require. In service the aggregate number of revolutions day by day of the two drums are about equal. In spite of the fact that the line is in continuous service, a recent examination of the wearing surfaces of the gear teeth showed the original tool marks, indicating very little wear during their long service.
All journals run in hard brass bearings capacle of adjustment in either direction. Various means of lubrication are employed. The journals of the direction sheaves are supplied with a prepared grease about the consistency of lard, from a reservoir conveniently placed and connected with the pillow blocks by small pipes. The small beveled pinions in the drum driving gears are lubricated by oil fed from the reservoir in the shaft of each pinion through small oil holes in each bearing.
The steam generating equipment of the power station consists of eight Babcock & Wilcox boilers, two of which have recently been added. The boilers are of 104 h. p. each, i. e., they are guaranteed to evaporate per minute not less than 3120 lbs. of water at a temperature of 100 degs. F., under a steam pressure of 70 lbs. The boilers are set in batteries of two boilers each, and each battery has a heating surface of 2388 sq. ft.
THE ADOPTION OF ELECTRICITY AS AN AUXILLARY POWER.
The Brooklyn Bridge Railway is in many respects an ideal line for cable equipment. Indeed, so well is the cable fitted for this work that while electricity has been adopted for certain service, as will be described later, the Trustees of the bridge property are confident that it will never replace the cable for the work of heavy through transportation. The following are some fo the principal advantages of cable power for the Bridge Railway:
The absence of grade crossings permits the employment of a surface cable, avoiding at the same time the expensive constructin of a conduit, and permitting the easy inspection of the cable and sheaves and the employment of wear saving devices like the roller grip.
The route is short and straight and the traffic very heavy; conditions particularly favorable to high efficiency of cable apparatus.
The grades are steep and the descending load balances the ascending load, reducing the power required from the cable engines to a minimum.
The uniform speed given to the cars by the cable and that the cars, while attached to it, are spaced at regular intervals, eliminate from the operation of the trains a personal factor which might tend to accident from end collisions.
For switching the trains at the terminals, steam locomotives have, until recently, been used as well as to operate trains during the early morning hours when the amount of traffic was not sufficient to warrant the operation of the cable. The objections to these locomotives and the reasons which induced the Bridge Trustees to try as a substitute for them electric power, were described in full in the Street Railway Journal for March, 1896. The electric equipment has since that date been in process of installment, and is working under test.
The generating plant for the Bridge Railway is located in an extension to the building containing the cable driving plant and the engines are supplied with steam from the same boilers that supply the cable engines, so that if any accident disables the cable or its driving mechanism the steam is at once available for the load thrown on the dynamos.
There are two 400 k. w. Walker generators direct connected to two simple non-condensing vertical engines of the Porter-Allen type. The engines operate at 100 r. p. m. and are guaranteed to give at an initial pressure of 100 lbs. and at 1/4 cut-off not less than 600 h. p. each. As the electric equipment was designed principally to replace the locomotives in switching service at the terminals, the load is necessarily rapidly fluctuating between overload and no load and for part of the twenty-four hours will be practically nothing.
The switchboard is of the standard Walker construction with two feeders on each of three panels, two generator panels and one equalizer panel.
In considering the distribution of power through the feeders it is necessary to understand the conditions of bridge service. The major portion of the work is done on the Brooklyn end of the line since, in addition to the regular switching operations of the main line, the yards are located there and as from one-half to two-thirds of the trains are taken on and off before and after the rush hours and all are changed for cleaning during the day there is considerable yard switching. All this requires power. The next greatest demand for power comes from the New York Station, and ordinarily the Bridge itself takes no current except for lights and to supplement occasionally the grips on the car.
From the station, six feeders, each of 500,000 c. m. capacity, lead by the most direct path to the railroad track and so far as possible are parallel to and visible from them. Two feeders run to the New York Station and terminate there on a switchboard from which lead the taps to the different sections of rail. By means of taps to form the feeders to another switchboard located at the tilting sheaves, the track from the Station to the New York anchorage is supplied. Two more feeders run parallel to the tracks from anchorage to anchorage and are tapped in as shown in Fig. 20. They are made symmetrical because one side is as likely as the other to be used for shuttle trains at night or during blockades. The last two feeders supply the track from the Brooklyn station to the anchorage as well as the station itself and the yards. It will be observed that a number of switches, over forty in all, are used outside of the station. This enables a section to be readily cut off in case of derailment or trouble of any kind and when it is necessary to repair the track or the cable work. The principle has been observed that since the system was installed for railroad work, it should be put in the hands of the railroad men, and the switches have been placed in convenient places, and usually the track switch and the electric switch for that track are practically side by side, so that a man can throw both at once. The third rail is bonded with two No. 0000 Chicago bonds at every joint. The bonds are bent downward after coming out two inches from the web so as to hang slightly below the rail to allow the removal of fishplates or tightening of the bolts. As the cable was located in the center of the track, the third rail is placed on one side or the other , and its head is five inches above that of the running rail. Tracks on the main lines are 5 3/4 ins. between centers of rails, the third rail is 16 ins. center to center from one rail and 21 3/4 ins. from the other, Where there is single track, the third rail is ordinarily placed 19 ins. center to center with the nearest running rail. This distributes the wear over the entire face of shoe. At the end of each section of rail, a cast iron end piece was fastened with ordinary fishplates, having its upper face sloping from the rail head to the point. At eight places in the third rail, there are "dead sections", consisting of two rail lengths supplied in each case from the nearest feeder through a separate switch and insulated from the neighboring rails at both ends. These are placed at each end of a section that may be desirable to cut out so that the current cannot pass through from one live section to another section from which the current has been cut off through the front and rear shoes of the car as it passes over. For example, if workmen are on the north track on the suspended part of the bridge, the switches at the dead sections of both anchorages on that track are pulled as well as that on No. 4 feeder. Then a car in coming from Brook- lyn has one shoe on the anchorage section and one on the dead section, then both on the dead section, since that is 60 ft. long and the shoes are 32 ft. apart between centers and then one on the center section and one on the dead section. It, of course, makes the dead section temporarily alive, but this section is so short that no one can be hurt, as he must necessarily have gotten out of the way of the train.
The rail used for the conductor is the old four inch rail taken up last summer. At the time the track was relaid, the fish- plates were not taken off the old rail except every 200 and 300 ft. In re-erecting it for electrical use, it was raised by hand and laid on the ties; owing to its flexibility it could be handled in any length. The insulators were then put on the bottom flange of the rail between the ties for the length of a section. The rail was again raised by hand or a lever over the running rail and an insulator slid along until it was over its tie, the rail was lowered and the next one similarly placed. Two men followed and gauged the rail and fastened the insulator to the tie. It was bonded after erection and no insulators were broken by the method of raising or by the riveting of the bonds.
Seven rail lengths, 210 ft., were connected, forming a standard section, and an inch space left between the sections to provide for expansion. At the dead sections a four inch air space was left, no fishplates being used.
The motor equipment of each car consists of four General Electric 50 motors, which are capable of continuously exerting a horizontal effort of 1200 lbs. when mounted on a thirty-three inch wheel running at ten miles per hour. The motors are completely encased, and are watertight and dust tight. The armatures are slotted, each coil lying in its own slot, and the method of winding followed allows of the removal of any coil, with very little disturbance to the others. Each motor is provided with a roller which will come directly over the cable and prevent it from abrading the motor or injuring it in any way and from being injured itself.
Each car has also two K 14 controllers which are similar to the standard K type of controller, but adapted for four motors.
The method of contact adopted is clearly illustrated in Fig. 10, which shows one of the shoes, of which there are four to each motor car, two on each side. These are suspended from a support set between the journal boxes of each truck.
The cars have been lighted by electricity for several years, the current being taken from an overhead wire by means of a trolley of special design.
The trucks employed are of the McGuire L type and were designed especially for this class of work. Double equalizing bars spring supported on the journal boxes are used. On these equalizers are mounted two cross sills, from which are suspended the electric motors, so that the wheels, axles, equalizers and motors move together independent of the truck frame and car body. The brakes are located inside the wheels and surround the motor without interfering in any way with it. Two types of brakes are used, the Eames vacuum and hand brakes. Each is independent of the other, so that in case of accident to the vacuum brakes the cars can be controlled by the hand brakes. Further particulars of these trucks were published in the STREET RAILWAY JOURNAL for February, 1896.
The motor cars, of which twenty are now is use, measure 39 ft. 3 1/2 ins. over end sills. They are finished inside in mahogany with ceilings in light color decorated with gold. The cars have four doors, one at each end and one at the middle of each side. They are fitted with longitudinal seats having spring seats and backs covered with rattan. The trimmings are of solid bronze and the cars are heated with small hot water Baker heaters.
No account of the New York & Brooklyn Bridge would be complete without a description of the carefully planned and elaborate system of terminal facilities recently completed on both the New York and Brooklyn sides. In considering these terminal arrangements it should be borne in mind that a large proportion of the traffic across the bridge comes from New York business men who have homes in Brooklyn, and that the New York terminal is at about the center of the New York business district and within easy walking distance of the destination of most of the passengers. Greater care was therefore paid to the transfer of passengers from the Bridge Railway to the surface and elevated lines at the Brooklyn end than in New York.
In Brooklyn the bridge entrance is the main terminal of most of the Brooklyn transportation systems, both surface and elevated, and the plan of the new Brooklyn terminus is shown in Fig. 19. The elevated railroad systems in Brooklyn are two in number: the Brooklyn Elevated Railroad and the Kings County Elevated Railroad. The trains of the former run on a double track loop entering by way of Sands Street, and departing by way of High Street. There are two stations in the bridge structure with separate platforms for outgoing and incoming passengers, one on each street. During the time of heavy traffic it is intended that every other elevated railroad train on this line shall stop at the Sands Street station, and every other one, running over the second track, at the High Street station. During the hours of light traffic, the Sands Street station is not used. Each of these elevated railroad stations is just above the Bridge Railway platforms from which they are reached by flights of stairs.
The Bridge cars are run out from two platforms and the incoming trains discharge passengers at two other platforms, as shown, the empty cars being switched from the incoming to the outgoing platforms. The station of the Kings County Elevated Railroad is on Fulton Street, mid-way between Sands and High Streets, and is connected with the Bridge Station by an inclined gallery. Passengers from the trains of the Kings County Elevated Railroad pass horizontally along this gallery for about 230 ft. to the third floor of the Bridge Station, which is at the same elevation as the platforms of the Brooklyn Elevated Railroad stations, whence they descend by stairways to the center of the bridge railway platforms.
Passengers for the surface lines can either take their cars on Washington Street or on Fulton Street. Application has been made for terminal surface tracks on the Plaza shown in the engraving, and if this be granted the transfer of bridge passengers to the surface railways will greatly facilitated.
The new improvements at the New York terminal have been chiefly to facilitate the despatching of trains, the capacity of the terminal being practically doubled by the changes made. Formerly the cars discharged the passengers at one platform and were then switched to the outgoing platform. Two center platforms are now used, as shown in the engraving (Fig. 20). The entering trains discharge alternately on each side of the incoming platform and are then switched alternately to either side of the outgoing platform. Incoming passengers who wish to take the Third Avenue trains of the Manhattan Elevated Railway pass directly to the station of that railway without descending to the street, while there are also several entrances to the cable railway platforms.
The receipts of the Brooklyn Bridge from all sources for the year ending Dec. 31, 1896, amounted to $1,404,318.47 and the total expenditures to $1,640,490.24, the latter figure including heavy charges to construction account together with interest on certain New York City and Brooklyn bonds. A careful inspection of the items both of receipts and expenditures shows that the difference between the true operating receipts and the true operating expenses amounts to a sum equivalent to a return of about 2.3 per cent upon the original cost of the Bridge with its land, buildings, etc., assuming this cost to be in round numbers $15,000,000. This is not, to be sure, a large return, but certainly, considering the great value of the Bridge as a public work, it is gratifying to find that it is even measurably self-supporting and not a serious burden upon the finances of the two cities.
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