Front:
THE SPIRAL TUNNELS
PRIOR to 1908 Hector and
Field stations were sepa-
rated by such extreme grades
that four consolidation loco-
motives were required to haul
a trainload of freight over this
section. For about three miles
a grade of 4.5 per cent prevail-
ed - ten times the maximum
gradient normally permitted
on heavy prairie work.
By the construction of these
Spiral Tunnels this grade was
reduced to 2.2 per cent. From
the east, the track enters
Tunnel No. 1, 3,206 feet in
length, turns under Cathedral
Mountain at an angle of about
250 degrees on a 573 foot
radius, passes under itself and
emerges at the opposite portal
54 feet lower. Tunnel No. 2,
under Mount Ogden, has a
similar radius through an
angle of 232 degrees; it is
2,890 feet long and the grade
produces a difference in
elevation of about 45 feet
between portals. Thus the
railway traverses the valley
by three lines at different
elevations, and crosses and
re-crosses the Kicking Horse
River by four bridges. Two
engines can now haul a bigger
load up the valley than the
four previously used.
The two tunnels are a per-
fect maze, for the railway
doubles upon itself twice and
forms a rough figure "8" in
shape.
If the train is run
in two sections, passengers
are able to see the other
section making its way up
"the big grade" at a higher
or lower level.
T.R
WHITE DOTTED LINES REPRESENT THE ROUTE
FOLLOWED BY CANADIAN PACIFIC TRAINS
THROUGH THE FAMOUS SPIRAL TUNNELS.
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