The Richmond Virginian. (Richmond, Va.) 1910-1920, 1916-12-24
BIGGEST MT. TUNNEL
READY ON TINE

Seattle, Wash, Dec. 23.-Under
giant Mount Macdonald, In the Sell
kinks of British Columbia, the Can
adam Pacific Railway has just COM
pleted the longest double track
mountain tunnel in the western hem
isphere.
The eastern portal Is situated al
most Immediately under the little
town of Hermit. Three and one-half
years were allotted to complete the
work. which would have made the
date of completion December 81.
1916, but the method of construction
pursued by the engineers has reduced
this time SO that the tunnel was
opened practically three weeks before
that date.
This method consisted OF driving a
small working or pioneer tunnel,
through which was carried all the
working air. water and ventilating
pipes, as well as the material from
the headings in the main tunnel.
This pioneer bore was a small pre-
liminary shaft, seven feet by eight,
which paralleled the course Of the
main tunnel at a distance OF about
fifty feet. Cross-cuts were made
from the small bore to the line Of
the main tunnel about every 1900
feet. Drifts in each cross-cut were
driven in both directions.
In addition, the main tunnel work
was advanced from each portal. The
initial hearing was made as an eight
by eleven center heading and the en-
largement operations followed close
ly The advance headings met on De-
cember 10, 1918, and the enlarge
ment by the steam shovel had
advanced on that date three miles,
leaving two miles to complete. This
work was carried on at the rate of
a quarter mile per month.
The pioneer" tunnel Will serve as
ventilating shaft for the main tun-
mel.
The tunnel with q bearing under
Mount Macdonald was constructed
on tangent throughout Its entire
length of Ave miles. The maximum
depth Of rock above 1t Is $500 feet.
For about LOO feet at each end the
tunnel was constructed through clay
and boulders. the rest of the passage
being through solid rock, mica schist
and quartzite.
The tunnel is Twenty-Five feet
wide and twenty-four feet high.
One of the difficult engineering
feats carried out in connection with
1HG tunnel uHuSTta4hIflR WAS the III
version of the course of the Illicille-
waet River. To accomplish this a
deep trench nearly mile long was
dug on the left side OF the approach
es. This acts as a continuation Of the
original channel OF the river and d.
verts the stream past the cutting to
a point where an arched culvert turns
the water under the tracks again into
! the old creek bed on the right side
of the railroad.
The tunnel reduces the elevation Of
| the track through Rogers Pass by
| $50 feet and cuts out curvature to
/ the amount OF seven complete cir
| Giles. The highest point reached by
| the tunnel Is s,7a5 feet above sea
! level and 4.os5 feet from the extreme
height OF the peak.
The force OF men employed by the
contractors numbers 1900, and to
care for them model villages have
been established on both sides Of the
mountain.
The Canadian Pacific Railway four
| years ago bored two spiral tunnels
/ through Mount Cathedral and Mount
| Ogden In the Rocky Mountain ran-e.
/ eliminating what was known in rail-
/ way circles as the big HILL" between
! Field and Hector, British Columbia.
| The engineer who had charge OF the
/ tunnel undertaking which reduced
/ the grade to normal on the dig hill''
| spent two years seeking a favorable
| location for a tunnel through the Sell
| kinks He discovered a route six and
a quarter miles long. and later i'm
| proved on his first plan and develop
| ed the tunnel scheme.
The tunnel Is named 'Connaught,"
| after the late Governor General OF
| Canada. It cost ss,5oo.00o.