St. Paul daily globe. [volume] (Saint Paul, Minn.) 1884-1896, 1895-01-26
THE GREATEST TUNNELS.
Improved Machinery for Rum
ming Them Under Mountains.

Improved Machinery for Rum
ming Them Under Mountains.
Boston Transcript.
Speaking of the fremont street sub
way, which both the incoming and
outgoing mayors refer to as no longer
in the deba table stage, our cOnserva-
tiVeS are very timorOuS and behind
times about it, when ii is considered
that London is already threaded with
such works, that New York is to have
many miles of them, and that tunnel
ing is everywhere the engineering or
der of the day. All arrangements are
now reported to be completed for the
vigorous prosecution of work Oh the
great tunnel under the Simplon, be-
tween Switzerland and Italy. The
board of expert engineers appointed
last April to report on the proposed
methods Of the contractors has made q
favorable reply. The tunnel will be the
longest railway tunnel in the world.
a. rs feet, which exceeds the AZ, 145- feet
of the Mont Cents line, the 1913 feet of
the GOthard line, the 90. 5S7 feet of the
Arlberg, and the four and three-quar-
ter miles of the HOosac tunnel. I'm
like all other long doubIe-track tunnels,
the Two tracks viii not be carried in q
single large tunnel. but in two smaller
parallel ones IS feet apart between cen
ters and connected every $50 feet by
cross cuts. The average area of the
section of each of the tunnels is to be
about $50 square feet, the width Is feet
inches and the height Is feet.
The plans of the contractors are eX-
planned at length in a recent issue of
the organ of the Swiss Engineers So
ciety, and are quite different from the
As the contract calls for the completion
of one of the tunnels and the construc-
ton of a working gallery along the
line of the second as the first portion
of the undertaking, the contractors,
Brandt, Brandau & Co., of Hamburg,
have decided TO drive two galleries
from each end as the basis of the two
tunnels and to connect these every
$50 feet by crosS-cuts which the
contract calls for. One gallery
will be enlarged Immediately to
the full cross section to form
tunnel l, while tunnel will
be completed only when the first no
longer suffices for the traffic. The clear
section of gallery 2 will be used for
ventilation, and as it has an area of Sc
square feet it is believed to be ample
for the purpose. Its entrance will be
into it by powerful fans. The cross
cuts are to be closed except the two
end ones, so that the air must pass
in through gallery and out through
gallery l, thus maintaining a current
which is expected to ventilate the
workings sufficiently. The material eX
cavated in tunnel 1 is to be taken out
through the same tunnel in trains
drawn by steam engines which will go
back to the workings through gallery
and the cross-cuts. Both galleries
will be driven by hydraulic drills, three
or four at each heading, and II IS eX-
pected that the progress made with
them will be at the rate of 19 feet
day.
Recent improvements in the drills
have materially shortened the time re-
quired to make the holes for one blast,
and the efficacy of the latter is in
creased by reason of improvements i'll
explosives. The contractors also eX-
pect to make a considerable saving in
time by throwing the blasted rock
backward with hydraulic power at the
moment of explosion. Thus the rock,
instead of lying within a few feet of
the face. is scattered back for some
distance and the drills can be set up
again in a shorter time. The con-
tractors are to receive the sum of
50, 100000 when Tunnel No. and the
Gallery No. 2 are complete, and if this
part of the undertaking is not COM
pleted in five and a half years they
are to be fined $1,000 a day for the re-
mainder of the working period. There
is previous payment of ST. 51, 600 when
the power plant and the other appar-
atus for working are set up, but the
large payments are not due until the
first tunnel is ready for regular traffic.