[Illustration: PLATE L, FIG. 3.--TW 96, P.T. & T.R.R. Co. N.R. Div.
Terminal Station West. View looking West from Ninth Avenue Elevated
Railway, showing condition of work. May 26, 09.]

[Illustration: PLATE L, FIG. 4.--TW 104, P.N.Y. & L.I.R.R. Terminal Station
West. View from Tenth Avenue looking East, showing progress of concrete
walls. Aug. 7, 09.]

Along the north side, between Stations 186 + 50 and 187 + 50, the walls
supporting the adjoining back yards were of poor quality and had to be
renewed by the contractor before excavation could be done.

The excavated material was loaded by derricks on cars at the top of the
excavation, these cars being on tracks having a direct connection with the
disposal trestle, as shown by Fig. 1, Plate L. As soon as it could be done,
derricks were placed at the bottom of the excavation; tracks were then laid
out there, and the excavated material was loaded on cars at the bottom and
hoisted by derricks to cars on the disposal trestle. A locomotive was
lowered to the bottom of the excavation on August 25th, 1907, and a derrick
started operating at the bottom on August 27th, 1907. The commencement of
this work by derricks at the bottom is shown by Fig. 3, Plate LII. In
general, the disposal tracks were maintained about on the center line of
31st Street until the excavation had been carried as close to them as
possible, and on October 16th, 1907, they were shifted to the extreme north
side of the work, as shown by Fig. 2, Plate L. A portion of the old trestle
was left in place near Tenth Avenue, a derrick was erected thereon, and the
tracks were used for cars to receive the excavated material hoisted from
sub-grade. The disposal trestle was maintained in this position until such
time as it would interfere with the excavation, and then the tracks were