Vol. 17 No. 10
October, 1987
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Stay Safe in 87
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Massive Ventilation Building
"Hidden" By Steve Morris
Sneak Peek: Despite its size, the ventilation shaft building for the
Mount Macdonald railway tunnel, which is currently under construction, is designed not to be seen by tourists
travelling through the Glacier National Park.
Rogers Pass British Columbia - If you're driving through the national park here and you
miss CP Rail's 26-metre-high ventilation shaft building, it isn't because you need glasses or a guide;
the railway's engineers just planned it that way.
The 31,000-square-metrefacility, currently under construction on the slopes of Mount Macdonald, has been
designed in such a way that the millions of tourists who visit the area each year will never see it from the scenic
highway.
Hidden from view by hundreds of trees, the building is the heart and soul of a one-of-a-kind ventilation
system for the Mount Macdonald Tunnel, the longest tunnel in North America.
Its room full of fans and control equipment will provide fresh, clean air to the tunnel, allowing a train to pass
through every 30 minutes.
Without this ventilation system, it would take at least an hour to purge the 14.6-kilometre tunnel of
exhaust fumes generated by diesel locomotives.
"The ventilation building was one of many structures in the project that had to be carefully thought out because
they are smack in the middle of Rogers Pass in glacier National Park, and thus environmentally sensitive", said
John Fox, vice-president, special projects.
FOUR FANS
"Just below the ventilation building is the Trans-Canada Highway and a picnic area. We had to be
conscious that it would not distract from the view and park-like setting".
The building is located 349-metres above the tunnel, atop a divided ventilation shaft. Inside are four
2,250-hp, 4.3-metre-diameter fans that have been specially-designed and built
to provide and purge more than 14,000 cubic metres of air a minute to and from the tunnel.
The support foundations for each of the fans and motors alone measure 4.1 metres wide, 11.7 metres long, and 4.3
metres high, and require 200 cubic metres of concrete.
COMPUTER SYSTEMS
The foundations are designed to insulate resonant frequencies developed by the fans from the surrounding soil. If not
insulated, these frequencies could cause an unwanted settling of the foundations.
The mammoth fans will be controlled by two computer systems which will monitor a train's progress through the tunnel
and control 22 separate ventilation and cooling activities, as well as operate two sets of doors in the tunnel.
The control system will interface with CP Rail Centralized Traffic Control (CTC) system in Revelstoke to facilitate
train movements to the tunnel.
OPERATION
The doors, located midway through and at the east portal, play a key role in ventilating the tunnel, which will be
used by west-bound trains. (East-bound trains will continue to use the current rail line
through the Connaught Tunnel.)
As a train approaches the east portal, the first set of doors will open vertically to let the train through. At the
same time, a fan at the east end of the tunnel and two fans in the ventilation shaft building will force cool, fresh
air down half the ventilation shaft towards the train.
As the lead locomotive approaches the midway point of the tunnel, a second set of doors will open and the remaining
two fans in the ventilation shaft building will then begin drawing air from the west portal towards the train and up
the other half of the ventilation shaft.
BACK-UP SYSTEMS
The fans will operate until the tunnel is completely purged of exhaust fumes.
In the event of a power failure, electricity will be provided by a General Motors EMD SD-60 diesel
engine linked to an AVK generator rated at 3,500 kilowatts. A second 600-volt stand by generator will
also be on hand to provide power to run lighting and the building's ventilation and control systems.
Faced with a short construction season, PCL Industrial Constructors has been racing against the clock to finish the
exterior of the building before the heavy snows of October and early November. With the exterior completed work can
continue inside.
The building is expected to be completed and the necessary equipment installed by next summer, well before the Rogers
Pass Project is completed later in 1988.
Race Against Clock: Workmen are racing against an approaching winter
in order to complete the exterior of CP Rail's ventilation shaft building.
This CP Rail News article is copyright
1987 by the Canadian Pacific Railway and is reprinted here with
their permission. All photographs, logos, and trademarks are the property of the Canadian Pacific Railway
Company.
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