Ashtabula weekly telegraph. (Ashtabula, Ohio) 1880-1886, 1880-07-02
worl.Ing Under tho Hudson.

AZ the foot Of Fifteenth street. Jersey
City, a low wooden building has been
erected, which has the appearance ofan
oyergrown shanty rather than the begin
ming Of an important and difficult work
This building contains the office of the
Hudson Tunnel Railroad Company, and
also the engines, electric generator and
air compressor. In the center Of the
building a shaft thirty feet in diameter
has been sunk to the depth Of sixty feet.
Its lower portion is used as receiving
tank for the mud removed from the tun-
neil About midway down the shaft has
been iloored over Jutting out from the
river side Of this shaft is what appears to
be large iron boiler. This is the "air-
lock" an air tight chamber made Of one
half inch rolled iron and six feet in diam
eter and fifteen feet in length, through
which everything passes in entering or
leaving the tunnel. By its use persons
passing In are gradually accustomed to
the changes in air pressure, about six
minutes usually being taken in the opera
ton. From the air lock, which is a little
above the top of the tunnel proper. the ex-
cayatiOn was extended at a gradual de-
cline until the required depth was reach
ed-about sixty feet below high water
The exterior structure or shell of the tun-
mel consists Of "A cylinder Of one half inch
boiler plate iron, with a line Of brick two
feet thick securely anchored 10 it. The
river on the line Of the tunnel is about
$500 feet in width, and its bed is largely
composed Of blue clay, with a mixture Of
sand and other substances.
The excavation Is begun at the top, an d
carried forward in sections. The plates Of
which the iron casing Is composed are
placed in position as fast as sufficient
space is excavated, These plate are two
and one-half feet in width by three and
six feet In length. They are bolted TO-
gether by means Of angle irons secured to
their edges. The brick work is laid as
rapidly as a circle Of sections is complet-
ed The silt is thrown back into a pool
into which is running stream of water
forced in from pump in the shaft by the
pressure of the condensed air in the tun-
mel. This water, carrying about One-half
of the silt, is blown out by six inch
pipe into the receiving tank. The re-
naming portion is carried into the finish
ed tunnel
The office is connected with the tunnel
by telephone and the electric light is used
both in and out of the tunnel work being
carried on throughout the "a hours. An
average Of about A feet OF the tunnel is
finished daily. -.-r1.s "A
The top of the tunnel will have an aver.
age distance Of about % feet below the
river bed. This makes necessary IA con
siderable grade as the riverut some points
reaches the depth of go feet BY the
agency of compressed air, at a pressure of
II TO 30 pounds TO the square inch, this
mixture of water clay and sand in the cx-
cavation is keptso firmly in position that
IL might be worked forward in terraces or
benches, thus obviating all necessity for
staying or braces while eXcavating the
silt or placing in position the upper sec
lions of the iron casing. So eOmpactly is
the silt held that an experienced work
man with a sharp shovel will carve out
and shape the top or sides as easily as If
he was cutting cheese, and can prepare
exactly the place for each sheet.
The entrance to hetunnell on the New
Jersey side will be alta point about three
quarters Of mile from the river The
terminus inNew York lhs not been set
tied, but the tunnel will enter the city al
the foot of Leroy street. An underground
depot will be used, and nowhere will the
track be less than fifteen feet below the
surface. The approaches on either side
Will be 26 feet in width and 2i feet IN
height, with double track but Under the
river herewith be two tunnels, side by
side, each Is feetin heighth and 10 feet
in width, and each containing n single
track, Work is now In progress in only
one Of these tunnels, but everything is in
readiness TO begin the adjoining one in a
few dogs, when operations cap be. begun
on the New York side also With ap-
proved facilities il is expected that each
section will be advanced al rate of five
feet per day.-7iI6uHe. p y