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+The Project Gutenberg EBook of Transactions of the American Society of
+Civil Engineers, Vol. LXVIII, Sept. 1910, by Alfred Noble
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910
+       The New York Tunnel Extension of the Pennsylvania Railroad.
+       The East River Division. Paper No. 1152
+
+Author: Alfred Noble
+
+Release Date: March 28, 2006 [EBook #18065]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK TRANSACTIONS OF THE AMERICAN ***
+
+
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+
+Produced by Juliet Sutherland, Sigal Alon and the Online
+Distributed Proofreading Team at http://www.pgdp.net
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+
+AMERICAN SOCIETY OF CIVIL ENGINEERS
+
+INSTITUTED 1852
+
+
+TRANSACTIONS
+
+Paper No. 1152
+
+
+THE NEW YORK TUNNEL EXTENSION OF
+THE PENNSYLVANIA RAILROAD.
+
+THE EAST RIVER DIVISION.
+
+BY ALFRED NOBLE, PAST-PRESIDENT, AM. SOC. C. E.
+
+
+
+
+A general outline of the work included in this Division has been given
+by General C. W. Raymond, M. Am. Soc. C. E., in the first paper of the
+series. The few pages following are intended only as a note to connect
+his paper with the more detailed descriptions of the execution of the
+work, which will be supplied by the Resident Engineers in immediate
+charge.
+
+Soon after the Company's project was made public, in the latter part of
+1901, borings were begun in the East River, and a few weeks later in
+Manhattan and Long Island City. A preliminary base line was measured on
+the Manhattan side, and temporary transit stations were established on
+buildings from which all borings in the river were located. The river
+borings were all wash-borings made from a pile-driver boat. After the
+results were plotted on the map, contour lines were drawn to indicate
+the rock surface, and profiles along the tunnel lines were plotted from
+the contours; as the borings were preliminary to the final location of
+the tunnels, and in many cases at some distance from the tunnel lines,
+considerable divergence from the actual rock surface was expected, and
+realized in a few places, yet on the whole the agreement was very good.
+The borings revealed two depressions or channels where the rock surface
+passed below the grade of the projected tunnels, these depressions being
+separated by a rock reef which extends down stream from Blackwell's
+Island. In 32d and 33d Streets in Manhattan, borings were made from the
+river to the station site at intervals of about 100 ft., wash-borings
+and core-borings alternating. In Long Island City, where the tunnel
+lines were to pass diagonally under the passenger station building and
+passenger yard of the Long Island Railroad and under streets and private
+property, the arrangement of borings was less regular, although the
+alternation of wash-borings and core-borings was carried out as far as
+practicable. After the final location of the work, additional borings
+were made, particularly on shaft sites and also along the approaches and
+in the Sunnyside Yard, Long Island City.
+
+A triangulation was carried across the river with a measured base on
+each side. It was impossible to measure directly between the extremities
+of either base. The bases were measured with 100-ft. steel tapes,
+supported every 20 ft., stretched with a uniform pull, and frequently
+compared with standardized tapes. On account of the crowded condition of
+the streets during the hours of daylight and evening, most of the work
+was done between 10 P. M. and 5 A. M. Similar measurements were made in
+the streets along the tunnel lines. Angle readings were repeated many
+times, as is usual in such work. Fig. 1 shows the triangulation, the
+street measurements being omitted.
+
+Levels were first transmitted across the river by simultaneous
+observations of the river surface; then by several repetitions, across
+Blackwell's Island and the narrow channels on each side, where the
+longest sights were about 1100 ft.; and, finally, by several lines
+through the tunnel of the East River Gas Company at 71st Street.
+
+The franchise granted by the City of New York provided for the sale to
+the Railroad Company of the portions of 32d Street between Seventh and
+Eighth Avenues, and between Eighth and Ninth Avenues. Later, the Company
+acquired by purchase the portion of 32d Street between Ninth and Tenth
+Avenues. The franchise granted sub-surface rights under streets around
+the station site to within 19 ft. of the street surface under Seventh,
+Eighth, and Ninth Avenues; to within 30 in. of the street surface under
+31st and 33d Streets, except that, under the sidewalks opposite the
+station, that is to say, the south sidewalk in 31st Street and the north
+sidewalk in 33d Street, the construction must be at least 5 ft. below
+the street surface. In carrying out the work, full use of these rights
+was made under Eighth Avenue, but only under such portions of Seventh
+and Ninth Avenues as were indispensable for access by trains to the
+station area. It was not practicable to make full use of the rights
+granted under 31st and 33d Streets without incurring great expense for
+supporting adjacent buildings or for injuries to them, and, after
+careful consideration, the arrangement shown in the plans was decided
+on, making about 45% of the sub-surface area under these streets
+available at track level.
+
+[Illustration: FIG. 1.--Triangulation System East River Tunnel]
+
+The work of the East River Division at this site embraced the excavation
+to the depth necessary for railroad tracks, and the building of a
+retaining wall extending in 31st Street from the east side of Ninth
+Avenue to the west side of Seventh Avenue, thence northward along
+Seventh Avenue for a distance of 155.5 ft.; also a retaining wall in 33d
+Street from the west side of Seventh Avenue to the east side of Ninth
+Avenue, and thence southward along Ninth Avenue for a distance of 136.3
+ft. This work was placed under contract June 21st, 1904, with the New
+York Contracting and Trucking Company, and later assigned by that
+company to the New York Contracting Company-Pennsylvania Terminal, and
+was carried out under the direction of George C. Clarke, M. Am. Soc.
+C. E., as Resident Engineer, by whom it will be described in detail.
+
+[Illustration: PLATE IX.--Map of Portion of Manhattan Island from 23d to
+40th Streets, Showing Former Topography From Map Made by Gen. Egbert L.
+Viele in 1865]
+
+The station tracks leading eastward from the station will converge under
+Seventh Avenue and for some distance farther east, and pass into two
+three-track tunnels, one under 32d Street and the other under 33d
+Street, at the respective distances of 192 and 402 ft. from Seventh
+Avenue. A typical cross-section of the three-track tunnel is shown on
+Plate XII. The converging sections were considered as easterly
+extensions of the station, and were not included in the East River
+Division. Within a few hundred feet (Plate XIV), the tracks are reduced
+to two, each passing into a single tube, the two tunnels under each
+street being formed in one excavation, the distance between center lines
+of tunnels being 20 ft. 4 in. This construction has been termed a twin
+tunnel, and a typical cross-section is shown on Plate XII. The tunnels
+continue on tangents under the streets to Second Avenue where they curve
+to the left by 1° 30' curves, passing under private property, gradually
+diverging and passing through shafts just east of First Avenue. About
+350 ft. west of the shaft, the divergence of the two lines from each
+street becomes sufficient to leave a rock dividing wall between them,
+and thence eastward each tunnel is formed in a separate excavation. A
+typical cross-section of the two separated tunnels is shown on Plate
+XII.
+
+It thus appears that eastward from the station the lines constitute a
+four-track railroad, each track being in a separate tunnel; for
+convenience of the work these lines were designated _A_, _B_, _C_, and
+_D_, from north to south.
+
+[Illustration: PLATE X.--Manhattan Shaft, Lines _A_ and _B_]
+
+At an early date, when the organization of the engineering staff was
+taken up, Charles L. Harrison, M. Am. Soc. C. E., was appointed
+Principal Assistant Engineer. He was directly in charge of all parts of
+the work, and all Resident Engineers reported to him. George Leighton,
+M. Am. Soc. C. E., was placed in charge as Resident Engineer of the 33d
+Street lines from the west end of the three-track tunnel to the shaft
+and also eastward from the shaft under East River. As he was not then
+able to endure the effects of compressed air, the work under the river
+was transferred to James H. Brace, M. Am. Soc. C. E., as Resident
+Engineer. Before the completion of the land tunnels under 33d Street,
+Mr. Leighton accepted more responsible employment elsewhere, and Mr.
+Brace assumed charge of them also. Francis Mason, M. Am. Soc. C. E., was
+in charge as Resident Engineer of the 32d Street lines during their
+entire construction, and also of the tunnels extending these lines
+eastward from the First Avenue shaft under the river.
+
+The work just described as the 32d and 33d Street lines, terminating at
+the easterly end at the First Avenue shafts, was placed under contract
+on May 29th, 1905, with the United Engineering and Contracting Company.
+The plans then provided for three-track tunnels from the west end of the
+work under the contract eastward 1,628 ft. in 32d Street and 1,418 ft.
+in 33d Street to the west line of Fifth Avenue, with a descending grade
+of 0.4%; this was to constitute, in a degree, an extension of the
+station, where trains could stand without brakes while awaiting signals
+to proceed to or from the station. From Fifth Avenue eastward to the
+lowest point under the river, the grade was to be 1.5% on all lines.
+Later, during construction, when excavating westward under 33d Street
+from Fifth Avenue, the surface of the rock was broken through,
+disclosing quicksand; within the next few days trial drill holes through
+the tunnel roof at 32d Street and Fifth Avenue showed a thin cover with
+quicksand above it. The conditions had been indicated in a general way
+by borings made before construction was begun, but they proved to be
+rather worse than anticipated. On the topographical map of Manhattan
+Island, made by General Egbert L. Viele in 1865, is shown a watercourse
+which had its source near what is now Broadway and 44th Street, flowing
+thence along the west side and south end of Murray Hill, passing under
+the present site of the Waldorf-Astoria Hotel, crossing 33d Street at
+the point where the rock surface was broken through in the tunnel
+excavation, as above stated, crossing 32d Street at its intersection
+with Fifth Avenue, where trial drilling showed thin rock cover over the
+tunnel excavation, passing thence eastward a short distance south of 32d
+Street, which it recrossed near Third Avenue, and finally discharging
+into the East River near 34th Street, and a little west of the present
+First Avenue. The ancient creek apparently followed the course of a
+valley in the rock, the valley having become filled to a considerable
+depth with very fine quicksand. This concurrence of depressions in the
+rock surface with the watercourse shown on Viele's map was noted in so
+many places and the difficulties of construction were so serious at
+these places, that a section of the map showing the old topography along
+and adjacent to the station and tunnel lines is reproduced in Plate IX.
+
+[Illustration: PLATE XI.--Long Island Shaft. Lines _A_ and _B_]
+
+The unfavorable conditions developed at Fifth Avenue affected both the
+construction of the tunnels and the maintenance of adjacent buildings.
+It would be necessary to construct the tunnels in open cut for a large
+part of the way westward, causing serious inconvenience to the public;
+the buildings were mostly of the older class, founded in earth, but
+there were several modern high buildings with foundations in the same
+material; some of these had been built since the tunnels were planned.
+In view of these added risks and the increased cost of construction, the
+value of the three-track construction was reconsidered, and two
+important changes were made in the plans. The first of these was to
+continue the twin tunnel westward to Sixth Avenue in 32d Street, and to
+a point 180 ft. west of Sixth Avenue in 33d Street; the twin tunnel
+being 9-1/2 ft. less in height than the three-track tunnel and 9 ft.
+narrower, the change reduced the difficulties considerably. Where the
+three-track tunnel was thus eliminated, there was no longer objection to
+a steeper grade, so that, going eastward from the station, a grade of
+0.8% in 33d Street and 0.9% in 32d Street was substituted for the
+original 0.4% grade. From the west line of Fifth Avenue eastward short
+sections with descending grades of 0.3% connect with the original 1.5%
+grade near Madison Avenue. The effect of these two changes--type of
+tunnel and grade--was to lower the roof of the tunnels at Fifth Avenue
+about 15 ft., which made it practicable to avoid open cutting east of
+Sixth Avenue.
+
+A full account of the construction of the cross-town tunnels will be
+given by the Resident Engineers.
+
+Permanent shafts were made on both sides of the East River, those in
+Manhattan being located a few feet east of First Avenue, and those in
+Long Island City being located, one in the so-called Annex Slip, the
+other in the pier just south of it. The two railroad lines coming from
+32d Street in Manhattan, and curving to the left at Second Avenue, are
+about 34 ft. apart between centers at First Avenue, and it was
+convenient to make the shaft large enough to cover both lines. Borings
+had shown that the excavation for the tunnels would break out of the
+rock about 200 ft. east of First Avenue. It was desirable to carry the
+tunnel excavation eastward from the shaft in normal air far enough to
+permit of building at least 50 ft. of tunnel and installing air-locks,
+so that compressed air might be available when the rock surface was
+broken through. The location adopted, and shown on Plate XIII, had the
+further advantages that the rock surface was several feet above the
+level of the top of the tunnels, and access to the river for receiving
+and discharging materials could be had without crossing any street.
+Similar reasons governed the location of the north shaft for the lines
+from 33d Street. On the Long Island side of the river there were only
+two feasible locations meeting these conditions, particularly in respect
+to a safe thickness of rock above the tunnels, one near the pierhead
+line, the other just outside the bulkhead line, and for many minor
+reasons the latter was preferable. The center lines of each pair of
+tunnels were 37 ft. apart, and each shaft, therefore, was made to cross
+both lines of a pair, the same as on Manhattan side of the river. It was
+not expected, however, that the Long Island shafts could be built
+conveniently or the tunnels begun from them in normal air.
+
+The decision to make the shafts of permanent construction was based not
+only on the desirability of having access to and egress from the tunnels
+near the banks of the river for convenience of the workmen or exit for
+passengers in case of accident, but to facilitate ventilation; these
+locations divide the entire lengths of tunnels east of the station into
+three parts, two of which were approximately 4,000 ft. each, and the
+other about 5,500 ft. The accident risk was believed to be very small,
+while much weight was given to the feature of facilitating ventilation.
+Further studies have enhanced the importance attached to ventilation,
+and it is now intended to provide appliances for mechanical ventilation
+at all shafts. The plans of the shafts are shown on Plates X and XI. The
+caissons for the shafts are of structural steel, with double walls,
+filled between with concrete, including a cross-wall between and
+parallel to the tunnels. All these structures were fitted for sinking
+with compressed air, if that should prove necessary.
+
+Although borings had shown that rock would be found at all the shaft
+sites several feet above the tunnel level, it could not be determined in
+advance of excavation whether the caissons would have to be sunk to full
+depth; if sound, unfissured rock were found, the sinking could be
+stopped above the tunnel level; but, if not, the caissons, in any case,
+would have to be sunk far enough to permit placing a water-tight floor
+below the tunnels, and the tunnels themselves begun through openings in
+the side-walls of the caisson; such openings, therefore, closed by
+removable bulkheads, were provided in all caissons.
+
+[Illustration: PLATE XII.--Typical Tunnel Sections]
+
+As already stated, the grade of 1.5% from Fifth Avenue eastward was
+fixed with reference to the lowest point of the river bed in order to
+give the requisite cover over the tunnels at the deepest point of the
+channel on the west side of the reef, where the river bottom was about
+60 ft. below mean high tide for a short distance. On the other hand, as
+the use of compressed air in building the tunnels was anticipated, an
+excessive depth below the water surface was to be avoided as far as
+possible; it was necessary, however, to continue the descending grade
+some further distance until the tunnels were mostly in rock, so that
+drainage sumps under the tunnels could be made readily. Eastward from
+the sumps the tunnels had a rising grade of 0.7% to the established
+bulkhead line on the Long Island side, giving a cover at the points
+where the tunnels enter rock, a short distance westward, of about 10 ft.
+(if the dredging plane should be fixed at some future time at 40 ft.
+below mean low tide, as may be reasonably anticipated). Eastward from
+the bulkhead line, Tunnels _A_, _B_, and _D_ have ascending grades of
+about 1.25%, while Tunnel _C_ rises at the rate of 1.9% in order to
+effect a crossing over Tunnel _B_ west of the portals. This feature was
+introduced in order to place the two west-bound tracks together through
+the Sunnyside Yard, and the heavier grade, being downward with the
+traffic, was not objectionable.
+
+The arrangement of grades and tracks in the approaches and in Sunnyside
+Yard would require the introduction of too much detail to be taken up
+here, but will be dealt with in the paper on the Sunnyside Yard.
+
+It was recognized from the inception of the project that the tunnels
+under the East River would be the most difficult and expensive section
+of the East River Division. The borings had shown a great variety of
+materials to be passed through, embracing quicksand, coarse sand,
+gravel, boulders, and bed-rock, as well as some clayey materials. (See
+Plate XIII.) The rock was usually covered by a few feet of sand, gravel,
+and boulders intermixed, but, in some places, where the rock surface was
+at some distance below the tunnel grade, the material met in tunneling
+was all quicksand; the nearest parallels in work previously done were
+some of the tunnels under the Thames, particularly the Blackwall tunnel,
+where open gravel was passed through. Before the plans for the East
+River tunnels were completed, work had been resumed, after many years'
+interruption, in the old Hudson River tunnels between 15th Street,
+Jersey City, and Morton Street, Manhattan, and sand materials were
+passed through for a short distance. These experiences satisfied nearly
+all the engineers in any way connected with the work that the shield
+method was the most suitable for the East River tunnels, and the plans
+for the work were based on its adoption. (See Plate XII for
+cross-sections, etc.) Other methods, as stated by General Raymond in the
+introductory paper, were advocated, particularly caisson constructions
+and the freezing process, the latter being urged very strongly, and,
+when proposals were invited, in October, 1903, bidders were informed
+that alternative methods would be taken into consideration.
+
+Bids were received and opened on December 15th, 1903. Only one bidder
+proposed to carry out the work on the basis of unit prices, but the
+prices were so low that the acceptance of the proposal was deemed
+inadmissible; no bid based on caisson methods was received; several
+offers were made to perform the work by the shield method, in accordance
+with the plans, for a percentage of its cost, and one was submitted, on
+a similar basis, covering the use of the freezing method. The firm of S.
+Pearson and Son, Limited, of London, England, submitted a proposal for
+building the tunnels by the shield method, on a modification of the
+percentage basis, and as this firm had built the Blackwall tunnel within
+the estimates of cost and was the only bidder having such an experience
+and record in work in any way similar to the East River tunnels,
+negotiations were continued between that firm and the railroad company.
+
+The original plans and specifications contemplated that all tunnels
+between the First Avenue shafts in Manhattan and East Avenue in Long
+Island City would be shield-driven, and that work would proceed
+simultaneously eastward from the First Avenue shafts and both eastward
+and westward from the Long Island City shafts located west of Front
+Street at the river, requiring twelve shields. When making their
+proposal, S. Pearson and Son, Limited, suggested that shields might be
+started from the east end of the work and arrive at the Front Street
+shafts as soon as these shafts could be completed, and proposed sinking
+a temporary shaft transversely across all four lines near the east end
+of the work just west of East Avenue, from which, within a short time,
+to drive toward Front Street by the use of shields. The railroad company
+accepted the suggestion for the additional shaft, although the greater
+part of the tunnels east of Front Street was built without shields.
+After several months of negotiation, a contract was entered into on July
+7th, 1904, with S. Pearson and Son, Incorporated, a corporation of the
+State of New York organized by the English firm for the purpose of
+entering into and carrying out this contract. The main features had been
+agreed upon, and work had begun about two months before. The contract
+embraced the permanent shafts in Manhattan and Long Island City, the
+tunnels between these shafts, and their extension eastward in Long
+Island City to East Avenue, including in all about 23,600 ft. of
+single-track tunnels. The contract had novel features, and seemed to be
+peculiarly suitable for the unknown risks and the unusual magnitude of
+the work. A fixed amount was named as contractor's profit. If the actual
+cost of the work when completed, including this sum named as
+contractor's profit, should be less than a certain estimated amount
+named in the contract, the contractor should have one-half of the
+saving. If, on the other hand, the actual cost of the completed work,
+including the fixed sum for contractor's profit, should exceed the
+estimated cost named in the contract, the contractor should pay one-half
+the excess and the railroad company the other half; the contractor's
+liability was limited, however, to the amount named for profit plus
+$1,000,000; or, in other words, his maximum money loss would be
+$1,000,000. Any further excess of cost was to be borne wholly by the
+railroad company. The management of the work, with some unimportant
+restrictions, was placed with the contractor; the relations of the
+engineer, as to plans, inspection, etc., were the same as in ordinary
+work, and the interest of the contractor to reduce cost was the same in
+kind as in ordinary work.
+
+[Illustration: PLATE XIII.--Plan and Profile. East River Tunnels]
+
+On account of the extent of the work embraced in this contract, and the
+dangerous exposure to compressed air required in most of it, it was
+divided into three residencies; two of these, including also the
+cross-town tunnels, have been described; the third, with S. H. Woodard,
+M. Am. Soc. C. E., as Resident Engineer, embraced all tunnels from the
+easterly end of the work near East Avenue in Long Island City to the
+meeting points under the river and also the permanent shafts in Long
+Island City. A few months after the execution of the principal contract,
+the work to be done was extended eastward 107.5 ft., across East Avenue.
+The extensions of the tunnels were built without cast-iron linings and
+with an interior cross-section of the same height as the tube tunnels,
+but somewhat narrower. The work was also extended westward from the
+First Avenue shafts to include the excavation of top headings in each
+tunnel for a distance of 100 ft. and an enlargement to full size for 50
+ft. The borings having shown that soft earth existed below the grade of
+the tops of the tunnel under the passenger station building of the Long
+Island Railroad on the east side of Front Street, and that earth of
+varying character would be met in places beyond the station building
+under the railroad tracks in the passenger yard and the street car
+tracks in Borden Avenue, it had been decided, before proposals were
+invited, to extend the metal lining eastward to East Avenue, at the east
+end of the work embraced in the original contract, where the rising
+tunnel grades approached the surface of the ground so closely that their
+further extension would be in open cut. In places where the tunnels were
+wholly in rock, the weight of the cast-iron tunnel lining was reduced
+43%; where the surface of the rock was below the top of the tunnel, but
+above the axis, the reduction of weight was somewhat less, about 25%;
+notwithstanding these savings, the cost of the tunnels was probably
+increased by the use of the cast-iron lining; on the other hand, when
+passing through bad ground, a section of tunnel could be made absolutely
+safe more quickly by erecting the lining as soon as a length of a few
+feet of tunnel was ready; under a crowded passenger yard, this feature
+had great value.
+
+The execution of the work under this contract will be described fully by
+the Resident Engineers.
+
+The plant assembled by the contractors is believed to be the most
+extensive ever placed on a single piece of work, and will be described
+in detail by their Managing Engineer, Henry Japp, M. Am. Soc. C. E.
+
+For convenience in receiving materials to be used in construction, and
+to facilitate the disposal of excavated materials, one pier was leased
+on the east side of the Hudson River, two on the west side of the East
+River and three on the east side. Excavated materials from the station,
+the cross-town tunnels, and the river tunnels, were placed on barges
+furnished by Mr. Henry Steers under several contracts embracing also
+the disposal of the materials. In the earlier part of the work, they
+were used as fill in the freight terminal of the Pennsylvania Railroad
+at Greenville on the west side of the Upper Bay; when the fill at this
+place was completed, the materials were sent to the tunnel company's
+yard on the Passaic, at Harrison, N. J., and a small part to the
+embankment in the Meadows Division. On account of the occasional closing
+of the Passaic by ice, this involved the possibility of, and to some
+extent resulted in, interruptions to the work of excavation. The
+contract for the cross-town tunnels carried an option in favor of the
+company to require the contractor for those tunnels to dispose of
+materials at a stated price, and in the latter part of 1907, when the
+excavation in these tunnels was being pushed rapidly, the railroad
+company, unwilling to incur the responsibility for delays during the
+winter, availed itself of this option. The disposal of materials was an
+important part of the work, and will be dealt with more fully by the
+Resident Engineers.
+
+[Illustration: PLATE XIV.--Map and Profile, Cross-Town Tunnels]
+
+At the time the contract was made with S. Pearson and Son, Incorporated,
+it had not been determined whether mechanical ventilation would be
+provided for the tunnels, and therefore the contract with that firm did
+not include the final concrete lining at the shafts, above the inverts
+of the tunnels. After the adoption of plans for mechanical ventilation,
+in the latter part of 1908, the plans for lining the shafts with
+concrete, including flues for conducting air to the tunnels, and
+stairways for ingress and egress, were completed, and the work was
+placed under contract; it will be described in detail by F. M. Green,
+Assoc. M. Am. Soc. C. E.
+
+At the east end of the work under the Pearson contract, the rising grade
+of the tunnels brought them so near the surface of the ground that their
+extension eastward could be carried out more readily in open cut than by
+tunneling. The locations of the portals could be varied somewhat, and
+they were built on rock which was found in rather narrow ridges at
+convenient places. Tunnels _B_ and _D_ have a common portal; Tunnels _A_
+and _C_ have separate ones, the portal for Tunnel _C_ being located
+about 800 ft, west of the others as a result of its crossing over Tunnel
+_B_, as already explained. Eastward from the portals, the track system
+expands, in order to provide connections with the tracks of the Long
+Island Railroad to and from Long Island City, with the New York
+Connecting Railroad and New England lines, and with the storage and
+cleaning yard known as the Sunnyside Yard extending to the west side of
+Woodside Avenue, 2-3/4 miles east of the East River. (Plate XV.) The
+yard and approaches are designed to avoid grade crossings by opposing
+trains. The various general features of the yard and tunnel approaches,
+bridge crossings, and street closings, have been described in sufficient
+detail by General Raymond in the introductory paper.
+
+[Illustration: PLATE XV.--Plan and Profile of Lines _A_ and _B_, and
+Sunnyside Yards]
+
+For convenience in placing the work under contract, a line was drawn 10
+ft. west of Thomson Avenue, dividing the work east of that embraced in
+the Pearson contract into two parts. The work west of the line was
+placed under the immediate direction of George C. Clarke, M. Am. Soc.
+C. E., as Resident Engineer, with Naughton Company and Arthur McMullen,
+Contractors; Mr. Louis H. Barker was Resident Engineer of the part east
+of the dividing line, with the Degnon Realty and Terminal Improvement
+Company as the principal contractors. The substructures of the several
+bridges in or across the yard were included in these contracts, but the
+superstructures were carried out by various bridge companies, and other
+minor features were executed by other contractors. More complete
+descriptions of the plans and of the execution of the work will be given
+by the Resident Engineers.
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Transactions of the American Society
+of Civil Engineers, Vol. LXVIII, Sept. 1910, by Alfred Noble
+
+*** END OF THIS PROJECT GUTENBERG EBOOK TRANSACTIONS OF THE AMERICAN ***
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