bed. The problem differed from that presented
by the usual foundation excavations in New York City in magnitude only,
and the methods were not unusual, but were adaptations of the usual ones
to exceptionally large work.

PIERS AND TRESTLE FOR DISPOSAL.

The most rapid and economical handling of all excavated material to
scows was made possible by the Tunnel Company procuring from the New
York Central and Hudson River Railroad Company the pier at the foot of
32d Street, North River, known in the earlier stages of the work as Pier
No. 62, but subsequently changed to Pier No. 72, and thus referred to in
this paper. This pier was occupied by a freight-shed used by the New
York Central Railroad Company, under a long-term lease from the City,
and that Company had to make numerous changes in their tracks and
adjoining piers before No. 72 could be turned over; the contract for
the excavation, therefore, required the contractor to procure any piers
needed previous to and in addition to it. Under this clause of the
agreement, the contractor procured one-half of the pier at 35th Street,
North River, which was used for the disposal of all material excavated
previous to May 22d, 1905, on which date Pier No. 72 was first put in
service.

As the type of plant the contractor would elect to use could not be
determined, previous to the letting of the contract, a general plan for
Pier No. 72 and the trestle approach, suitable for either trains or
wagons, was attached to the contract, and the details were worked out
afterward. The method adopted was by train, and a two-track approach to
the pier was provided. Beginning on the east side of Ninth Avenue, at
the south line of 32d Street, at an elevation of 20 ft. below the
surface, crossing under Ninth Avenue and to the center line of 32d
Street, it rose on a 1.5% grade in open cut to the surface of 32d Street
at a point 500 ft. west of Tenth Avenue, from which point it rose above
the surface of the street on a timber trestle to Tenth Avenue, which was
crossed overhead. West of Tenth Avenue the line changed by a reverse
curve to the south sidewalk of 32d Street, and continued on a timber
trestle, practically level, to the New York Central Yard tracks near
Eleventh Avenue. These tracks and Eleventh Avenue were crossed overhead
on a through-truss, steel bridge, and a column-and-girder construction
on which the two tracks separated to a distance of 29 ft, between center
lines, so as to brin