The San Francisco call., 1896-05-03
SOME FAMOUS TUNNELS.
Triumphs OF Modern Engineering in
Europe and America.

Triumphs of Modern Engineering in
Europe and America.
One OF the most famous tunnels outside
of the United Kingdom is that of the
Mont de Cenis or Col de Frejus, which has
length of seven and half miles (actually
$3.50 feeD through Mount Gents, and
which connects the provinces of Savoy
and Piedmont. This wonderful under
taking was proposed by NJ. Medal, and
plans for its construction were drawn
in 1s4S; but it was not until far into
the fifties that the plans were approved
and the undertaking decided on. The late
King Victor Emmanuel of Italy initiated
the work OF excavation by setting the bor-
ing machinery in motion on August 81,
1857.
AT first the ordinary method of piercing
by manual labor was adopted, steam be-
ing adopted in 1860, and compressed air
alterward to the finish. the boring beng
competed in December, 1870. The en-
gineers engaged on this gigantic operation
were NM. Grattoni, Grandis and Sonn-
veillier, and the total cost of the work was
f2, 900, 600. The first experimental trial
trip was made on September 13 and occu-
pied forty minutes, and the tunnel was
formally inaugurated by the passage
through of train of twenty-five carriages
III LWGDbi IuluuleS OD CeDIenDeT Ii, 1911.
the regular service commencing on Octo-
Der IL, 1871. In the Arlberg tunnel the
work was commenced in 1880 and COM
pleted in little over three years, the dis
tance being 6 1-5 miles and the cost f1O8
per yard.
Another famous tunnel is that which
passes through the Mont st. Gothard,
which is the longest in the world, being
8,480 feet in length. 1t traverses the CEN
ter of Switzerland at height of from 5000
to 1900 feet above the sea. 1t was COM
menced in 1872, and was opened in 1882
ten years having been occupied in its con-
struction. 1t has had very important
effect upon the commerce between Italy,
Switzerland and Germany. This tunnel
was bored out by means of mechanical
drills, the progress made being thirteen
feet per day.
One of the most famous instances of sub.
aqueous tunneling in the United Kingdom
was that of the Severn tunnel, which runs
for length of four and One-third miles
was commenced in 1873 and completed in
1886, Messrs. Hawkshaw, Son, Hayter and
Richardson being the engineers. The bed
OF the Severn is formed principally of
marls, sandstones and conglomerates, over
living highly inclined coal measures, states
and sandstones, which are also exposed to
the bed of the river. The tunnel is made
almost wholly in the lias and coal measure
formations, except at its eastern end, where
its passes through gravel. Much water was
met with throughout andin 1879 the work
;ngs were flooded for some months through
a large land spring on the Welsh side, and
which water had to be diverted. At an
other time the workings were flooded by
water which burst through hole in the
r1ver-bed, and this hole 16 feet by 10 feet,
had to be filled up with clay, and the
works completed beneath it. The greatest
amount excavated in any one week was
5000 cubic yards. Another tunnel, though
it be OILY one mile in length, is that known
as the Mersey, the whole of'the excavation
in which, amounting to 320,0 900 cubic yards,
was got out by hand LABOR, as to have used
heavy blasting would have shaken the
rock. The work took six years to carry
out, being opened in 1886, and Messrs.