Alpena weekly argus. [volume] (Alpena, Mich.) 1871-1893, 1882-03-08
The Hoosac Tunnel.

Inc railroad tunnel through the
Hoosac mountain between Troy and
Boston is the most costly and, in some
respects, the most remarkable piece Of
engineering yet accomplished in Amer
lea, and few facts, gathered from a
history of the enterprise in the March
Atlantic, will be Of general interest.
Though but recently completed, the
work was first projected over 60 years
ago, and, odd enough, its projectors
urged its necessity not for the purpose
of a railroad but canal. They ar
gued that for Boston to retain its share
of the western traffic it must build a
canal to meet the Erie canal at Albany
In 1926 the legislature of Massachu.
setts appointed missioners to ascer,
tain the practicability of such a canal.
After some preliminary surveys, the
commission reported the canal entirely
practicable, and as one Of the means
for raising the necessary funds they
urged the establishment of State lot.
terry.
The canal project, however, soon
gave place to railroad project, the
survey for which was made in 1927
Locomotives were yet almost unknown,
and the plan for the proposed railroad
contemplated such relays of horses as
would make it possible to go from Bos
ton to Albany in four days, and the
cars were to be so constructed that the
horses could get on and ride on all
down grades. AT this time the cost OF
the proposed tunnel was estimated at
less than 100000, but by the year
1850, when the surveys of the noun
tain were undertaken, the estimate had
increased to 100000. After various
contracts with private parties had been
thrown up and less than one-fifth Of
the tunnel had been constructed, the
State appointed a commission in 1863
to complete the work. A central shaft
1923 feet in depth was sunk, and by
working each way from its bottom as
well as from the two outer ends of the
tunnel the boring progressed more rap.
idly. Still the drilling by hand was
so slow and the difficulties from foul
gases, etc., were 80 great that the work
might still have been abandoned, had
it not been for the fortunate invention
of the Burleigh percussion drill, which
served the double purpose of Fastening
the work and ventilating the shaft.
The first train passed through the
tunnel April 8, 1875. but it was not
officially declared open for business
till July /, 1876. The total cost was
about $14,000,000, though with the
present experience and improved ap.
pliances it is thought the work might
have been done for $4,000, 900 and in
one-quarter the time expended upon it.
The mathematical calculations were
of the most difficult character and were
verified in a wonderful manner. Hav.
ing settled upon the eastern and west
ern points Of the proposed tunnel, q
line was run over the mountain, which
rises irregularly over 100 feet above
these points, to determine the length
of the tunnel. This line was run with
steel tape line 100 feet in length, and
even the sag in each length of the tape
was carefully calculated. The actual
length Of the tunnel when completed
only differed from its computed length
by 85-100ths of foot in distance Of
four miles and three-quarters. More
wonderful still, when the headings from
the central shaft and from the eastern
portal came together, the alignments
swerved from each other five-sixteenths
of an inch, which is an unparalleled
feat in engineering. 1t was extraor
dinary, considering the difficulty Of
getting an exact perpendicular in the
deep central shaft where the best
plumb lines kept up constant os
cillating motion. With the best en-
gineering talent in Europe the opposite
arms of the Mont Gents tunnel had 9
divergence Of more than half yard