Connaught Tunnel is an underground passageway.
Connaught Tunnel . At the time it was built , the Connaught Tunnel was the longest railway tunnel in North America . The tunnel was designed by John G. Sullivan who joined the Canadian Pacific Railway in 1900 and eventually became Chief Engineer for Canada . A tunnel is an underground passageway , dug through the surrounding soil/earth/rock and enclosed except for entrance and exit , commonly at each end .