The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1906-09-18

and. owing 10 their peculiarly satIsfac
| tory character, this work has been pushed
| forward With almost unprecedented
| rapidty.
The chief assistant engineer. Mr.
| James Forgio, a Scotchman, designed the
hydraulic sliding platforms with which
| the shields IRE equipped. Ii is on tbsss
platforms that the men stand In making
| the excavation ahead OF The tube itself.
| the platforms slide out as the work ad-
yances and the eXcavated material ia
| dumped back through the shield upon
tram cars, which carry 1t back to the
| shaft.
Mr.. Forgic was the principal assistant
to the distinguished tunnel engineer.
Greathead, In the construction OF the
Waterloo e. City railway tunnel under
the River Thames in 1894.
Inc contractors, the O'Rourke En-
gineering Construction company. began
operations in the subaqueous tunnels on
April IL, 1904. the nrst boring beginning
on the Manhattan side. On September
operations on the New JERSEY aide wero
begun, deep shaft having been sunk on
each Side nrior TO the beginning of the
actual borkaE
quietly lilo work went on, and the pub
lie heard OF little that was happening,
Accidents were remarkably few, There
was only one death that could be traced
10 me eHects Oh compressed air. there
were inevitably cases OF the bends"
TWO physicians have been in constant at
tendance at the works and everybody
who enters one OF the tubes has TO under
go rigid examination. Comfortable
quarters, well heated and we'll ventilated
are provided for the workers. and hot
conee is given to them, as a stimulant
when they emerge from compressed air.
How a Tunnel Is Bored
The tube Itself consists of a ser,es n,
Iron rings. and the installation of every
ring means progress OF two and a half
leet. Eleven plates and key piece to
go at the :op complete the circumference
ana an entire ring weighs about fifteen
tons. The castiron plates, or sections OF
the ring, have fianges at right angles TO
the surface, and 1t is by these that the
successive rings are held together with
bolts. Hydraulic rams placed against
the nanges every few inches around the
tube, push the shield forward at q max
imum pressure of 3400 tons: IL the pres
sure OF the air in the tube be taken into
account the pressure upon the shield is
increased TO 4400 tons
Inc shield Itself weighs 1914 tons, II
has nine doors in it, and through these
comes the rock or sand or silt. or what
ever the material through which the
tuoe must be driven, Thirty men work
IN gang, and there are three shifts in
the day OF twenty-four hours. The rec
ora progress SO far Is Ave rings or twelve
ana ha-f feet in eight hours. Men OF all
nasionalities have built the PENNSYLVANIA
luoes under the Hudson, negroes having
done a large part OF the job Lazlness
Is something the contractors never had
TO contend with; they say there must be
something about the compressed air
which generates energy and enthusiasm.
Tor the "muckers" vie with one another
TO make the record OF rings
Perhaps there has never been an en-
gineering project in which theory and
practice were so nearly in agreement.
The engineers calculated the difficulties
closely. and a really remarkable system
or reports has been In effect from the
hrst day. Every morning Mr.. Jacobs has
known the progress made the day before.
10 the very inch. and the amount OF rock
and soil cNcavated. TO the cubic foot. The
Pennsylvania railroad officers and the
contractors hold this perfect system and
the thoroughness OF each days work
chiefly responsible for the promptness of
the meeting OF the tubes.
EngiT>'crs say, TOO. that no project was
ever carried out where the emphasis was
so entirely upon the results rather than
upon the money Ii cost TO attain them
Records have been kept with unprece-
dented accuracy and fullness, and they
have been corrected. revised and re-re-
Vsed with bewildering frequency.