The Mount Macdonald Tunnel was built between 1984 and 1988 and was part of the $600 million Rogers Pass project. It marked the largest expansion of capacity since the Canadian Pacific Railway was completed in the early 1880’s. It is located in the Selkirk Mountains of British Columbia and was made by CPR to supplement the nearby Connaught Tunnel. Being 91m lower than the Connaught Tunnel, the Mount Macdonald Tunnel climbs at a lower grade. This allowed CPR to remove the pusher locomotives needed for the Connaught route.
At 9.1 miles (14km), the Mount Macdonald Tunnel is the longest railway tunnel in the Americas. It is 5.1m wide and 7.8m high, and was the first tunnel to use the concrete “Pact-Track” floor system. This system eliminates the need for wooden ties and rock ballast, reducing maintenance costs. The tunnel is also equipped with a ventilation system that includes four 1.68-megawatt fans, a ventilation shaft, and a control and monitoring centre.