structure temporarily, and, as there is an expansion joint
at each column, and as the transverse girders carrying the central track
system are not rigidly attached to the longitudinal girders carrying the
outside tracks, the central track could not be supported by supporting the
outside tracks; therefore, independent supports for each track, in the form
of overhead girders, had to be provided. The columns rest on brick piers,
each having four 2-in. anchor-bolts. The brick foundations on the west side
are wide in order to allow a 24-in. water main to pass directly beneath the
columns. The foundations are usually on rock.

[Illustration: PLATE XLVII, FIG. 1.--TW 4, P.N.Y. & L.I.R.R. Terminal
Station West. View of 9th Ave. looking Northwest from 32nd Street, prior to
commencement of work. April 23, 06.]

[Illustration: PLATE XLVII, FIG. 2.--TW 17, P.N.Y. & L.I.R.R. Terminal
Station West. View of East side of 9th Ave. looking North from a point 100
feet south of 33rd St. showing condition of work. July 23, 06.]

[Illustration: PLATE XLVII, FIG. 3.--TW 25, P.N.Y. & L.I.R.R. Terminal
Station West. View showing permanent and temporary supports of 9th Ave.
Structures, looking Northwest from 31st. St. April 24, 07.]

[Illustration: PLATE XLVII, FIG. 4.--TW 28, P.T. & T.R.R. Co. Terminal
Station West. East side of 9th Avenue, North of 32nd St. looking West,
showing rock excavation and supports of 9th Avenue structures. Aug. 17,
07.]

Fig. 1, Plate XLVII, shows the elevated railway structure and the street
surface prior to the commencement of the work.

The east track is used for north-bound local trains, the west track for
south-bound local trains, and the central track for south-bound express
trains between 7 and 9.30 A.M. and for north-bound express trains between
2.30 and 7 P.M. It is said that an average of 90,000 passengers are carried
over this structure every 24 hours.

_Surface Railway Structure of the New York City Railway Company._--This is
an electric surface railway of the ordinary type, the rail and slot being
bedded in concrete, with cast-iron yokes every 5 ft. There are manholes
every 100 ft., and cleaning-out holes every 15 ft. Power conduits are
bedded in the concrete on the east side of the east track.

_Forty-eight-Inch Brick Sewer._--This sewer was in the center of Ninth
Avenue, with the invert about 12 ft. below the surface, and manholes about
100 ft. apart, and had to be abandoned in this position to