Route No. 48, Section No. 2.- Extends from about Beekman and William streets under private property and William street to Pearl street. Contractor, Smith, Hauser & MacIsaac, Inc. Date of contract, December 7, 1914. Contract period, 28 months. Summary of contractor's bid, $2,254,670.

Working drawings were completed and shop drawings checked prior to 1917.

Route No. 48, Section No. 3.-Extends under Old Slip, the East river, Clark street, Fulton street, to junction with First Subway in Brooklyn. Contractor, Flinn-O'Rourke Company, Inc. Date of contract, August 6, 1914. Contract period, 42 months. Summary of contractor's bid, $6,469,915.25. The contract for this section was let in combination with the Whitehall-Montague Street route. This section consists of two singletrack, cast-iron tubes 1712 feet in diameter.

All working drawings, except for minor details, were issued prior to 1917, and shop drawings checked.

Studies were made during the year for the construction of a protective blanket over the tubes at the foot of Old Slip.

Construction: Route No. 48, Section No. 1.-At the beginning of the year excavation was complete from Church street to Broadway and from Park row to William street, and partly complete from West Broadway to Church street and from Broadway to Park row, under the Post-office building. The subway structure was substantially complete, except station features, from Church street to Broadway, and was fully complete from Park · row to William street. During 1917 excavation was finished from West Broadway to Church street and under the Post-office building, and the structure built within these limits. Throughout the extent of this section, excavation extended below ground water level and required constant pumping from sumps located in the vicinity of Broadway. Backfilling is complete and temporary pavement placed. Restoration of subsurface structures was also completed.

Work under the Court House and Post-office building included the completion of the underpinning during the year, as well as the completion of the subway structure, and the transfer of the building supports to the subway roof.

Certain work remains to be done, such as restoration of the permanent street surface and of the sub-basement of the Postoffice, including the replacing of machinery and appurtenances. Boute No. 48, Section No. 2.— During the year work on this section consisted of completing the Wall Street and Fulton Street stations; the completion of backfilling throughout the section; the completion of vault and subsurface restoration; restoration of sidewalks, and the placing of temporary pavement in the roadway. The work of subsurface restoration was greatly complicated, due to the narrowness of the street and the great number of these structures to be taken care of. A subway entrance was constructed through the building on the north side of Pine street west of William street, and consideration given to an entrance to the Fulton Street station through property near the corner of William and Ann streets. The restoration of permanent pavement remains to be completed.

Route No. 48, Section No. 3.-At the beginning of the year the excavation of the river headings had been completed and the cast-iron lining erected throughout the tunnels, except for 393 feet in the north tube and 394 feet in the south tube, where the tunnels were in the rock reef in the middle of the river. The excavation of the Manhattan and Brooklyn headings had been carried on to a meeting point in the rock in advance of the tunnel shields. The erection of the cast-iron lining in the north tube was completed March 9 and in the south tube April 4. The lines and grades laid down in each heading met within an inch, and the shields were driven without any serious deviation throughout the entire length of each tunnel, so that the contractor proceeded after the meeting of the headings to make the tunnels water-tight preparatory to removing the compressed air.

The excavation of the land headings on this contract was completed October 28, when the south shield reached the end of the section. Both shields were continued on the next contract, Route No. 33, Section No. 3, which work is being done by the same

contractor.

The maximum air pressure used on the work was 371⁄2 lbs. and as the work of caulking and grommeting the cast-iron lining proceeded the pressure was gradually reduced until it was entirely

removed on May 23, when the tunnel was practically water-tight. The work of placing the concrete lining was started June 12. The surveys made during the time the air pressure was being removed, and subsequently, showed that there was no settlement or distortion of the lining.

The record made on this work in tunneling under compressed air is noteworthy, as there was not a single "blow-out” under the river, and but one death due to compressed air sickness. It is of interest to note, in this respect, that there were 401,387 decompressions during the prosecution of the work and, with the exception of the single fatality, there were no serious cases of compressed air sickness. Further, the tunnel shields were driven under the streets of Brooklyn without any serious disturbance to overlying property, the result being obtained through very careful excavation and grouting methods. The maximum progress in tunneling during 24 hours was 32.5 feet, during one week of six working days 128.1 feet, and during one month 385 feet.

The progress in linear feet made in the excavation of the tunnel headings during the period of tunneling is summarized as follows:

The materials encountered in the river headings were fine sand, clay and rock, and in the land headings, coarse sand, gravel and boulders.

The progress in linear feet made in placing concrete lining in the different tunnel headings is summarized as follows:

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