The line became an important one for the CP with its connections to the Union Pacific Railroad and Portland, Oregon.

Completion of the Spokane International now meant that the CP could compete with the Northern Pacific Railway and Great Northern Railway lines for transportation between the Midwest and the Puget Sound area (in conjunction with the Union Pacific Railroad subsidiary Oregon-Washington Railroad and Navigation Company west of Spokane).

Express passenger service was soon introduced on the line via the Soo-Spokane Train De Luxe.

The locomotives were later repainted to UP's yellow and gray paint scheme, but retained their SI lettering.

The line remains in operation as the Union Pacific's Spokane Subdivision, an important connection between southern British Columbia and the northwest United States.