In this paper, it is proposed to describe the construction of thetunnels extending eastward from the easterly extension of the TerminalStation to the permanent shafts east of First Avenue.
They were located under 32d and 33d Streets from the station to SecondAvenue, and thence, curving to the left, passed under private propertyand First Avenue to the shafts, as described in a preceding paper.Typical cross-sections of the tunnels are shown on Plate XII.[B]
On May 29th, 1905, a contract was entered into with the UnitedEngineering and Contracting Company for the performance of this work.This contract provided that work on each pair of tunnels should becarried on from two shafts. The first, here referred to as the FirstAvenue Shafts, were located just east of that avenue and directly overthe line of the tunnels; the other two, called the Intermediate Shafts,were located on private property to the north of each pair of tunnels inthe blocks between Fourth and Madison Avenues. It was originallyintended to do all the work of construction from these four shafts.Workings were started both east and west [Page 392]from the Intermediate Shafts,and those to the west were to be continued to the Terminal Station.After the change of plans, described in a previous paper, it was decidedto sink a third shaft on each line. These were known as the West Shafts,and were located between Sixth and Seventh Avenues. Finally, it wasfound necessary to build a portion of the tunnels on each line west ofSixth Avenue in open cut. The locations of the shafts are shown on Plate XIV.[C]
The First Avenue shafts were built by S. Pearson and Son, Inc., for thejoint use of the two contractors, as described in the paper on thetunnels under the East River. While the shafts were being sunk, thefull-sized tunnels were excavated westward by the contractor for theriver tunnels for a distance of 50 ft., and top headings for 50 ft.farther. By this means, injury to the caissons and to the contractor'splant in the shafts by the subsequent work in the Cross-Town Tunnels wasavoided. The west half of the shaft was for the exclusive use of thecontractor for the Cross-Town Tunnels.
Contractor's Plant
The method of handling the work adopted by the contractor was, broadlyspeaking, as follows: Excavation was usually carried on by modificationsof the top-heading and bench method, the bench being carried as close tothe face as possible in order to allow the muck from the heading to beblasted over the bench into the full section. The spoil was loaded into3-yd. buckets (designed by the contractor and hereinafter described), bysteam shovels operated by compressed air, and hauled to the shafts byelectric locomotives. Electrically-operated telphers, suspended from atimber trestle, hoisted the buckets, and, traveling on a mono-railtrack, deposited them on wagons for transportation to the dock. Arrivingat the dock, the buckets were lifted by electrically-operated stiff-legderricks and their contents deposited on scows for final disposal. Thespoil was thus transported from the heading to the scow without breakingbulk.
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