Construction
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Construction |
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Construction of the New York, New Haven & Hartford By Gilbert O. Browne. The New York, Westchester & Boston Railway, part of which was put in operation last week, is a four-track electric line owned by the New York, New Haven & Hartford. It runs from White Plains, N. Y., to 174th Street, New York City, where it joins the Harlem branch of the New York, New Haven & Hartford, and when completed will be operated as a part of that system. Beside connecting with the Harlem branch at 174th Street, interchange of traffic will be made with the West Farms branch of the Interborough Rapid Transit subway at 180th Street and Morris Park Avenue. There is also a branch connecting with the New Haven main line at New Rochelle. The proposition of building a line along the general location of the New York, Westchester & Boston is not new. The original company was formed many years ago, and right-of-way was purchased from time to time. About ten years ago actual construction work was begun on the southern end of the road, but the company was unable to finance the project and was forced to give it up. Later, control of the road was bought by the New York, New Haven & Hartford, which relocated the line, and commenced construction work in 1908. Throughout its entire length, the line has been built to conform with the main line standard of the New Haven. The rail is 100-lb. section and creosoted ties with 22 in. of ballast are used. All bridges are of concrete and steel, and have been designed to stand heavy traffic at high speed. They are all waterproofed. The road will be operated by single phase current as a part of the New Haven electrical system, and multiple-unit trains will furnish the passenger service. There will be no freight service for the present. It is four-tracked from 174th Street to Mount Vernon, where two tracks diverge to White Plains, and two to New Rochelle. The entire line will be fenced in private right-of-way, protected with block signals and free from grade crossings. The maximum grade is 1.0 percent, except for one stretch of 2.5 percent from 174th Street, the junction with the Harlem branch tracks, to the south end of the West Farms Viaduct at 177th Street. The adjustment of alignment and grade at this point was one of the most difficult problems which the engineers encountered and the present location was adopted only after trying and discarding many others. Certain fixed street grades over which the tracks must have sufficient clearance, certain other points, like the junction point, at which the elevation was fixed, added to difficulties in obtaining right-of-way. All served to confine the possible solutions within narrow limits, and made the task one not so much of choosing the best, but of avoiding the worst. It was finally decided to carry the tracks over 177th Street, and this extraordinary grade was necessary to give the tracks sufficient clearance. The curvature is limited to 4 degs., except for one 6-deg. curve through Mount Vernon. From the Harlem river to about 174th Street the road will be operated over the tracks of the Harlem River branch, which will be completed so as to be available for such operation under a contract granting perpetual rights to the New York, Westchester & Boston. Just north of the present West Farms station on the joint tracks, the road diverges from the Harlem, and after crossing upper West Farms on a four-track steel viaduct 2,000 ft. in length, makes its first independent stop in the transfer station at 180th Street, near the eastern border of Bronx Park. The plans for this station call for a steel and concrete structure, 200 ft. wide by 540 ft. in length. Half a mile north the road crosses over the Morris Park viaduct. This viaduct is of reinforced concrete 400 ft long, and varying in height from 20 to 30 ft. It is very carefully designed architecturally, to secure a pleasing effect, so that the value of the surrounding property for residential purposes might not he impaired. The walls rise several feet above the track and have been finished with great care to add as much as possible to the appearance of the structure. All exposed surfaces are dense and smooth, and all exposed edges chamfered.
Immediately north is the Pelham Park subway, three quarters of a mile long. The company was forced to build this subway, instead of leaving an open cut, in order to obtain the right-of-way. After the cut was made, concrete piers were sunk and on these piers the steel framework was built. The general type of steel work is shown in the accompanying photograph and cross section. After the erection of the steel, the side walls and the top were filled in and the whole then waterproofed. It was then back-filled to the original grade. The interesting problem connected with the building of this subway was that of adjusting the grade and section of roof members to the conditions imposed by the varying levels of the streets which cross the subway. The clearance from base of rail to underside of roof is 18 ft. 6 in. Where the level of the street was higher than the average, the difference was taken care of partly by varying the gradient and partly by making a deeper and therefore more economic section of the I-beams in the roof structure. As few variations in section were made as consistent with economy so as to facilitate fabrication and erection. Another problem about which there was considerable discussion was as to the footings of the columns of the sidewalks. The base of the column rests on the same level as the floor of the subway. Some 3 in. from the near side of the column base a concrete wall 9 in. thick and 12 in. high was made, the intention being after the walls were in place to fill in the space between the column bases and this wall with concrete. There was some question as to whether this, combined with friction, would be sufficient to withstand the earth thrust. After the roof members and side curtain walls were in place, there was a heavy slide of material from the sides of the cut at one point, which forced the whole steel structure out of place, driving the bases of the columns up against the 9 in. wall, which held. This practical test settled any doubts. In general, to resist side pressure the whole subway structure acts as a unit, the floor system and the roof system dividing the horizontal thrust. At the station in the southerly end of the subway, and at the one in the middle, the stairway wells make it impossible to continue the integrity of the roof system, so at these points concrete retaining walls on each side of the subway are put in to take care of the earth pressure. The waterproofing is four-ply Barrett specification.
From this point to the East Sixth Street station at Mount Vernon there is comparatively light work, most of it embankment. East Sixth Street marks the southern end of the cut through Mount Vernon. This cut is from 20 to 40 feet deep, and is almost solid rock throughout. From the northern end of this cut the tracks run out upon the Columbus Avenue Viaduct. This viaduct is about 400 ft. in length, including the through girder bridge of 104 ft. span over the main line of the New York, New Haven, & Hartford R. R. The main girders are supported by towers resting on concrete pedestals; these towers are made up of 10-ft. girders supporting the main girders and resting upon H columns. In this structure each end of every longitudinal girder rests on a column and never on a transverse girder. This results in what at first sight appears a peculiar arrangement of columns in some places, particularly near the crossing of the New Haven tracks and the streets just north of the tracks. The columns are built up of 3/4in. plates and 3 in. single-bars, and their bases rest on 3/4in. bed-plates 48 in. x 56 in.
The girders used in the span over the New Haven tracks are exceptionally heavy, those in the center supporting two tracks weighing 90 tons apiece, and the outside ones, 54 tons. The distance between bearings is 104 ft. and the depth of the girders 10 ft. 6 in. The erection of this span was most interesting. The viaduct was built from the north end, as there was no point to the southward at which the steel could be brought in economically. The traveler used in the erection of the viaduct could handle the outside, 54-ton, girders alone, but not the three heavy girders. After the abutments and piers were built, the steelwork was erected up to the abutment north of the New Haven tracks. The two light girders were then erected by the traveler, one at a time, close together in a temporary position on about the center line of the bridge, the girders being lifted from freight cars on the New Haven tracks below, as shown in the accompanying photograph. A temporary floor system was put on these girders and a track laid. A derrick car was then run under the traveler and over this temporary track to the south abutment, from which position it erected the first span of the viaduct south of the abutment. Tracks were laid on this span and the derrick car run out on it (having first, of course, to be run back over the traveler and to the nearest point where it could be turned around so as to face the work on the long span over the New Haven tracks). Skids, consisting of rails on grillage, were then put on the two abutments. Two of the heavy girders were then lifted up from the New Haven tracks, each being handled by the derrick car and the traveller working together. These girders were put in temporary positions on the skids at each side of the light girders. The temporary track and floor system under the light girders were then removed and these girders were lifted out to their final positions. The two heavy girders were then moved on the skids to their final positions, which could not have been done before because of the position of the temporary track; and the third girder was lifted direct to its final position.
A few hundred yards north of this viaduct is the junction point where the tracks diverge, two running east through New Rochelle to the New Haven main line, and two extending north through Eastchester, New Rochelle and Scarsdale to White Plains. Immediately upon leaving the junction the former cross the Hutchinson River on a steel concrete floored viaduct 700 ft. long. The general type of construction of this viaduct is very similar to that of the Columbus Avenue viaduct. At Fifth Avenue, North Pelham, is a large concrete arch bridge which carries the tracks over the avenue below. The structure was designed to be a station also, and the combination is very effective. Between the station and Webster Avenue, half a mile north, there is considerable heavy cutting, and from Webster Avenue the road drops down for nearly a mile on a 1 percent grade to the junction with the New Haven main line. The White Plains branch extends northward after leaving the junction point and runs over a 30-ft. fill for several hundred feet before it also crosses the Hutchinson River. This fill, while not very large, is mostly earth and has given much trouble from settling particularly when concrete piers for the catenary bridges, which carry the electric contact wires, were being set. The bridge over the Hutchinson River is a single span deck girder, 105 feet long. Except for the cut at Wykagyl Station and the Essex Road crossing, there is comparitively little heavy work between this point and the heavy cut south of Quaker Ridge Station.
At Heathcote, a mile north, the site of the station was at the intersection of Heathcote Road and Palmer Avenue, all upon the same grade. Both roads were therefore raised for several hundred feet back from the station and are now carried over the tracks on steel girder bridges. Norton Avenue, which crosses the line half a mile from here, marks the southern end of a solid rock cut, less than 500 ft. long, but over which the company has had to build three bridges for street crossings. At Mamaroneck Avenue a tunnel section is used under the surface car tracks. The Mamaroneck Avenue cut, over half a mile in length, is the longest on the White Plains branch, and furnished much of the material for the great fill just north of it, which marks the White Plains station, the terminal of the line. Just before leaving the cut, the two tracks are increased to four, the two inside tracks are carried on a slightly rising grade to enable them to be carried on over the city when the Westchester Northern is completed. The outside tracks descend to the station and yards.
The system of electrification used on the New York, Westchester & Boston is the same as, in fact, a part of the general New York, New Haven & Hartford system; namely, a single-phase current of 11,000 volts on the contact wire, and a system frequency of 25 cycles. In adopting the voltage of 11,000 on the contact wire, the New Haven road has planned with the idea of permitting the operation of any adjacent company's equipment upon its own lines, or vice versa. This voltage is recommended as a minimum potential, it being recognized that there is no objection to a higher voltage on other lines individual to themselves where transmission economy can be obtained by the use of a higher voltage. The method of suspension of the contact wires for the New York, Westchester & Boston is quite different, however, from that now in use upon the New Haven main line, and shows the advance in catenary suspension design since the latter was erected several years ago. The wires are strung in sections between "anchor" bridges, situated about two miles apart, which take the entire strain from these wires in the direction parallel to the track. These anchor bridges are of heavy construction, 42 ft. in height to top of towers, and 61 ft. between centers of side frames. Between these bridges at intervals, which are normally 300 ft. but liable to change to meet special conditions, are the catenary bridges which support the contact wires and hold it in its proper position with respect to the track which it serves. They are of lighter construction than the anchor bridges, for there is no strain upon them, save from the weight of suspension wires, and wind pressure. The truss is supported by latticed posts, 31 ft. in height, and surmounted by towers with cross arms. The arms are so arranged as to carry feeder and signal wires, two on each arm. Seventy-five feet each side of the catenary bridge 3-in. I-beams, running across the four tracks, are hung from the 7/8in. main steel messenger strands; and on the beams are installed the suspension insulators. The lower insulators hold the track messenger, 5/8-in. steel strand, to which is pendant, by means of hangers, a copper trolley and a steel contact wire below. There is practically no corrosion of the steel wire, for it is constantly covered by a film of grease due to a generous amount of this material being placed upon the pantograph shoe of the cars. The steel wire is suspended from the conducting copper wire by means of metallic clips which fit very tightly into V-shaped grooves in the two wires, and afford a perfect connection between them.
In all cases, the masonry work has been completed first, and often before any earth work was done. Concrete was used throughout, not only in retaining walls, abutments, etc., but also in highway crossings, viaducts and stations. All exposed surfaces have been finished very carefully, and the general design has been so well planned that the masonry work is one of the most effective features of the road. For embankments, temporary wooden trestling was usually employed on work of any considerable size. The great majority of fills are of rock; the only large earth fill being on the White Plains branch just north of the junction point. The work has been carried out under the direction of J. L. Crider, chief engineer, and E. J. Langford, principal assistant engineer. The Columbus Avenue and Hutchinson River viaducts were erected by the American Bridge Company, under the direction of A. H. Rhett, structural engineer of the railway company. The general contracting work from White Plains to the junction with the New Rochelle branch was done by the Henry Steers Company, and by Murray & Gilbert; from this point through Mount Vernon by Lathrop & Shea; from this point to New York by the O'Brien Construction Company.
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