Branchline construction followed the completion of the Crowsnest Pass Route. The new main line passed through several important mining and lumbering areas but a branch line was required to reach the huge lead-zinc deposits at Kimberley where the Sullivan Mine was proving to be one of the most important in all of British Columbia. A branch line was built from North Star, just past Cranbrook to Kimberley, a distance of about 19 miles (30.5 km) by rail. The trackage was built in 1899-1900 and is still in service.
Ore and concentrates being moved from the Sullivan Mine at Kimberley and the Trail Smelter became one of the most important sources of traffic moving over the western parts of the Crowsnest Pass Route in British Columbia. The Sullivan Mine became part of the operations of the Consolidated Mining and Smelting Company (Cominco) which was controlled by the Canadian Pacific.