Engineering Wonders of the World
Volume I
Forfatter: Archibald Williams
År: 1945
Serie: Engineering Wonders of the World
Forlag: Thomas Nelson and Sons
Sted: London, Edinburgh, Dublin and New York
Sider: 456
UDK: 600 eng - gl.
Volume I with 520 Illustrations, Maps and Diagrams
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THE STORY OF THE SEVERN TUNNEL.
89
trance lift the water that finds its way into the
cuttings and tunnel. Ever since the opening
of the tunnel to general traffic the pumps
have been ceaselessly at work, emptying some
24,000,000 gallons a day into the Severn—a
quantity equal to about one-eighth of the water
supply of London, and sufficient to form in one
year a lake having a depth of 6 feet and an
area of about 7 j square miles! Travellers
through the darksome tunnel are probably
quite unaware that they pass close to fourteen
huge pumps, by which alone the safety of the
great tube is preserved. The Severn Tunnel
is a striking illustration of the extent to which
a submarine is handicapped in the matter of
drainage as compared with a big mountain
tunnel, which can be, and is, so graded as
to free itself of water by gravitation.
The ventilation of the tunnel is performed
by a huge Guibal fan, 40 feet in diameter,
which extracts the foul air through a shaft
at Sudbrook.
To conclude with a few striking facts and
figures. The construction of the tunnel occu-
pied fourteen years. In the busiest seasons
about 3,500 men were engaged.
The lining of the tunnel con- Facts
_ 1 • 1 ar,d
sumed 77,000,000 bricks — Figures
three - fifths of which were
made on the spot — laid in about 37,000
tons of Portland cement. For the necessary
blasting of rock 250 tons of explosives were
used.
The successful conclusion of this great under-
taking was a triumph for Sir John Hawkshaw,
Mr. Walker, and his doughty lieutenants.
There are much longer tunnels in existence, but
none of them has laid a heavier tax on the
perseverance and resourcefulness of its engineers
and their staff.
A TRAIN EMERGING FROM THE SEVERN TUNNEL.
{Photo, Great Western Railway Company.)