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Canadian Pacific's Connaught Tunnel

This photo taken from the rear platform of an observation car sometime between 1942 and 1959 shows the ventilation building at the west portal of the Connaught Tunnel - Andy Morin.


When the Last Spike was driven in Canadian Pacific's main line on 7 Nov 1885 at Craigellachie the tracks climbed over the Selkirk mountains through Rogers Pass. Snow conditions were so bad that the first winter there were no trains moving over that portion of the line. CPR solved the problem by constructing
31 snowsheds in the area of the pass over the next two years. Then on 4 Mar 1910 a huge avalanche came roaring down Mount Avalanche in Rogers Pass near shed 17 and killed 58 men who were in the process of clearing a previous avalanche from Mount Cheops. In February 1913 they announced the construction of a tunnel beneath the pass.
Such a tunnel would eliminate the need for maintenance of all those snowsheds, reduce the grade over the pass, and shorten the length of their main line.
Construction of this tunnel was commenced on 2 Apr 1914 by the firm of Foley Brothers, Welch, and Stewart. It went operational ahead of schedule on 16 Dec 1916.
The name chosen for this tunnel was Connaught, after the Governor General of Canada at the time, Prince Arthur Duke of Connaught.


 Internal link   Facts and Figures

Start date:  2 Apr 1914
Operational date:  16 Dec 1916
Length:  5.022 miles (8.082 kilometers)

Width:  20 feet (6.096 meters)
Grade:  0.95 percent
Cost:  $5.5 million

Trackage abandoned:  14.5 miles (23.335 kilometers)
Snowsheds abandoned:  31
Snowsheds length:  4 miles (6.437 kilometers)

 Internal link   Problems
The newly built double-tracked tunnel was plagued with falling rock, wet rails causing locomotive slippage, and insufficient ventilation. A concrete lining solved the loose rock problem and controlled water seepage. To solve the ventilation problem a large fan building was constructed at the western portal of the tunnel.

Over the years, and still so today, railway rolling stock has gradually increased in size. In 1959 the double-track through the tunnel was removed and a single track laid down the center of the tunnel to accommodate larger and higher equipment.

 Internal link   Today
Just as the Rogers Pass route with its snowsheds and looping track was a bottleneck for the railway in the early years, over time the Connaught Tunnel became a bottleneck too. Operation westbound through the tunnel required pusher locomotives to assist heavy tonnage up the hill to the eastern portal on a grade of 2.2 percent. An operational nightmare. So to solve the problem once more Canadian Pacific turned to tunneling. In 1988 a second route with two tunnels and a viaduct were put into operation. The short tunnel was named Mount Shaughnessy Tunnel (1.1 mile 1.77 kilometers long). The main tunnel was named the Mount Macdonald Tunnel. Lying 360 feet (109.728 metres) lower than the Connaught Tunnel and 9.11 miles (14.645 kilometers) long, the Mount Macdonald Tunnel reduced the grade over the Selkirks to only 1 percent on this new route.


Currently, loaded and heavier westbound trains use the lesser grade of the Mount MacDonald Tunnel route while the lighter eastbounds use the Connaught. However, this can change. For example, in 2002, a new tunnel lining was needed on the Mount Shaughnessy Tunnel which required the tunnel's closure to install it. All trains were therefore forced to use only the Connaught Tunnel. This necessitated reinstating pusher service from Rogers up to Stoney Creek siding near the east portal of the Connaught Tunnel. (See the Canadian Pacific employee news article "Push Comes to Shove in Rogers Pass" below.)
Operational conditions vary, so beware, you may find trains travelling in any direction on either route. Beware, indeed, that applies to any track anywhere.

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CP 9159 East exits the east portal of the Connaught Tunnel - Date/Photographer unknown.

 Internal link   New Information
Here's more information about the Connaught tunnel fans.
For many years, there was a row of CPR houses behind the west portal of the Connaught tunnel. These housed the fan operators and their families. Contrary to popular legend, the fans were never steam operated. Ancient one lung diesel engines connected to a large flywheel and enclosed squirrel cage fans forced air into the mouth of the tunnel via a short wooden false ceiling.
There was some skill involved in starting the one lung diesels. Once in full operation, the machines made a loud wooshing sound. Because of the noise generated by the fans, CP had a gong attached to the main line signal eastbound at the east end of Glacier.
Three quarters of a mile inside the tunnel was a lunar searchlight signal, connected to a short ABS block. When a westbound train entered this block, the bell on the signal outside the tunnel would start to ring. The control (home) signal for Glacier East was for many years located just inside the tunnel portal.
Sometime in the late 1960's, the operation of the fans was transferred to the train dispatchers in Revelstoke. For westbound trains entering the short block between the lunar and the east switch meant the fans were turned on automatically. The train dispatcher also had a start-stop switch as well as a status light on his/her panel.
Failures of the fans to start and stop were not uncommon, and following automation, there was no signal maintainer on duty at night to fix or monitor the fans.
Some time circa 1974, the Mountain Subdivision dispatcher had a steady fail light on his panel, and asked the crew of a westbound train going through the tunnel if there was any indication the fans were working.
When they exited the tunnel, they noted that the fan house was on fire. The original one lung engines were badly damaged and had to be replaced. The new engines to power the fans didn't require the tall steel smokestacks used by the original engines. The replacement engines didn't have a long service life, and in turn, they caught fire circa 1980, this time destroying the two tall fan houses.
The fan complex had to be entirely rebuilt as a lower structure. I think this is when the original engines were dumped beside the rail yard at Glacier. (A photo of the engine cylinders lying outside the fan building shows the date to be July 1972.)
The fans still work at Glacier, but see much less use.
CP's first EMD 710 engines were installed in the fans houses on the MacDonald tunnel. Again, the fan houses are automated, but have a much more sophisticated monitoring system for the Mountain Subdivision RTC's in Calgary to keep an eye on.
Phil Mason - 20 Apr 2013.

 Internal link   Still More New Information
Don Thomas has provided still more information regarding the Connaught tunnel:
It has commonly been suggested that the 1910 avalanche was the last straw for CP and the Rogers Pass line, and led directly to the decision to construct the Connaught Tunnel. This has been refuted by Gary Backler in his 1981 graduate thesis at University of British Columbia, "The C.P.R.'s Capacity and Investment Strategy in Rogers Pass, B.C., 1882-1916." Backler's research demonstrated that the avalanche was in fact not directly responsible for CP's subsequent decision to build the Connaught Tunnel. CP correspondence and files made it clear that the 1910 avalanche was considered a freak event at the time, as it came from a direction completely different from the usual avalanche paths in Rogers Pass. The cost of constructing a tunnel was found not to be worth the expense under conditions existing at that time. What changed CP's mind soon after was the need to increase capacity of the line, and specifically the 1912 decision to double track the main line between Calgary and Vancouver. This was an extension of the double tracking then under way between the Lakehead and Calgary, as well as elsewhere on CP. Traffic was increasing so rapidly that CP quickly began planning major changes to the mountain lines to accommodate a second track. This may seem ironic in view of the fact that the Canadian Northern and Grand Trunk Pacific were nearing completion and would compete for the same traffic the second track was intended to carry. Perhaps CP believed that a greater track capacity would help it compete for this traffic, and help mitigate the steeper grades and higher summits it traversed. CP may have anticipated that business would increase so much that even with competing railways there would still be an overload of traffic without the planned second track.
However that may be, the need for a second track through Rogers Pass, with heavy expenditures to build double track snowsheds, and to duplicate the extensive loop viaducts west of the pass and the large bridges on the east slope, made a tunnel more economical for the first time. Even then, however, a long tunnel roughly comparable to the present Macdonald Tunnel, or even one intermediate in length and elevation between Macdonald and Connaught, and with lower grades than the ruling 2.2 percent, was not found to be economic. After several iterations a five mile tunnel was found to be economic, and the present Connaught Tunnel was chosen. However it was initially planned to have a different east approach. This would have left the original line near Rogers, roughly where the Connaught and Macdonald tracks divide today, and rise at 1 percent much as today's Macdonald track does. About three and a half miles east of the Connaught Tunnel (roughly where Wakely siding is today) the grade would have increased to 2.2 percent, then eased off to just under 1 percent close to the east tunnel mouth. The purpose of this was to limit the length of grade greater than 1 percent to the minimum necessary to reach the elevation required for a five mile tunnel. The intention was to electrify from the base of this grade, through the tunnel to the present Glacier station. The chosen profile allowed for the shortest mileage of electrification, and consequently the smallest number of locomotives. Apart from the steep eastern approach grade, the electrification would have been similar in concept to those recently established for the Hoosac Tunnel or the first Cascade Tunnel, which were restricted to the tunnels and their immediate approaches. And if electrification had not proceeded, the pusher territory would have been comparable to, but shorter than, the existing line west of Rogers.
Since tunnel construction would take the greatest time of all the work required for this capacity project, it was started first. Subsequently the First World War caused most other phases of the double tracking project to be suspended or cancelled. So much had already been invested in the tunnel that it was now economic to continue building it. However the cost of the proposed new eastern approach for only one track was not justified by the small operating saving it would produce. The most economical way to approach the east end of the tunnel was to use as much of the existing east slope as possible. The route chosen diverged from the old line just around the curve west of Stoney Creek bridge, at a level grade until about half a mile from the east portal. From this point the grade gradually increased until it reached the tunnel's own grade of just under one percent, just east of the tunnel itself. This new alignment had the advantage of retaining the substantial investments in Stoney Creek bridge and all the other structures east of it including Surprise Creek and Mountain Creek, which would have been written off under the proposed lower double track alignment. By the time traffic increased again, larger locomotives allowed this line to handle it without the need for the lower approach, for a period of over fifty years. When a new tunnel was needed, the economics ruled against a new double track line (since Connaught would serve for eastbound traffic), but they did allow for a maximum 1 percent grade and longer tunnel, that had not been found economic in 1913.
Obviously a double track between Calgary and Vancouver would have affected other noteworthy sections of the line. In 1912, when the Spiral Tunnels were only three years old, alignments were proposed for second tunnels beside them. Between Revelstoke and Clanwilliam in Eagle Pass, there was a proposal for a viaduct beginning at the west end of Revelstoke yard, at the point where the track today begins to descend toward the Columbia River bridge. This viaduct would have begun to rise at 1 percent, heading to the right (more northerly) of the present bridge, then curving west to parallel the old line at a higher level and on an easier grade. The new line would return to the old alignment close to where the present old and new lines rejoin going west, which is where the grade on the old track eases out to about 1 percent. This line would have been a little shorter than the present new (westbound) track which similarly has a 1 percent maximum, but the cost of the viaduct would probably have been greater (adjusted for inflation) than the cost of building the new track on embankments in 1980.
Various alternatives were proposed to reduce the grade on Notch Hill as part of double tracking, including a tunnel and a new line across the shallow water offshore from Salmon Arm. None of them resembled the loop built for the present westward track.
The grade between Lake Louise and Field would have been lowered using a different route than the one adopted in the 1970s, rather closer to the original track and to Bath Creek. The principle would have been the same as with the present westbound track, with the increased grade beginning close to the station instead of starting to rise gradually before becoming much steeper at the top, as the original (eastbound) track does.
All of these works would have provided a maximum 1 percent grade against westbound freight, the dominant direction of traffic, between Calgary and Vancouver. This goal was not achieved until the present Lake Louise, Clanwilliam, Notch Hill grades, and Macdonald Tunnel were all completed by the 1980s. Elsewhere on this route, double track would have served to increase capacity but not, for the most part, to reduce grades. In some areas, particularly the Thompson and Fraser Canyons, both finding places for the second track, and constructing it, would certainly have been challenging.
Don Thomas - 16 Apr 2014.
Editor's Note:  The current co-production track through the Thompson and Fraser canyons certainly solves the problem of constructing a second track.

 Internal link   And Still More !
Doug Mayer has provided even more information, a drawing, plus two new photos regarding the Connaught tunnel. The photos and drawing may be found at the bottom of the thumbnail photos on the right side of this web page.
As you may know, the Connaught Tunnel will be 100-years-old in December 2016. Here's a sampling of what I know so far. Some of these "known" facts may turn out to be false:
The first official train through the tunnel was on 9 Dec 1916. Contrary to popular legend, the tunnel fans were never powered by steam. They were powered by large McIntosh and Seymour 4-cylinder oil engines of an early design. The engines weighed 156,000 pounds and were over 20 feet long and over 14 feet high. They operated at a speed of 190 rpm and burned Bunker C fuel oil. The engines were started with diesel fuel and then switched over to bunker C. The bunker C fuel required heating to keep it viscous, so a boiler room was built below the engine room on the south side. This may be where the steam legend came from. The fans were 12 feet 3 inches in diameter and 8 feet 3 inches wide. They were capable of delivering 700,000 cubic feet of air per minute. (Thumbnail photo number five shows a tank car on the building's siding which probably delivered the Bunker C fuel oil.)
Between 1921 and 1925 the tunnel was relined with concrete throughout it's length. Originally, only 7,800 feet of it were lined at the ends. The relining project was done while the tunnel was in use.
In 1931 the diverted Illecillewaet River broke through it's banks and flooded the west portal of the tunnel and it's approach with debris. (see the thumbnail photo).
In 1958 the tunnel was converted to single track.
In 1972 one of the fans houses had a fire that destroyed it's engine. At this time the old engines were discarded and newer type engines were installed. In 1976 another fire destroyed both fan houses requiring another rebuild with the result that the fan houses are now much lower. Some time after that the diesels were replaced by electric motors. It should be noted however that the original fans still exist.
Doug Mayer - 25 Apr 2014

 Internal link   News Articles
1910 - Death from Above
1921 - Lining the Canadian Pacific's Five-Mile Tunnel
1972 - A Tale of Glacier
2002 - Push Comes to Shove in Rogers Pass

 Internal link   Bibliography
Railway Contractors, The
Taylor, Geoffrey W.
Morriss Publishing 1745 Blanshard St. Victoria BC
1988 - Hard cover
6.25 x 9.25 inches - 16 x 23.5 centimetres
144 pages
64 photos
0 drawings
0 maps
Information about company that constructed the Connaught Tunnel.

 Internal link   Associated Web Sites
The Rogers Pass Project
Connaught Tunnel Mouse
Canadian Pacific Railway

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