Soo Line Corporation

Soo Line Railroad

Map of the Soo Line Railroad, with post-1961 Soo trackage still operated in red, former Milwaukee Road trackage now operated by Soo in blue, and former Soo trackage spun off to Wisconsin Central Ltd. (now part of the Canadian National Railway) in green; Dotted blue lines are abandoned
Reporting mark	SOO
Locale	North Dakota to Michigan via Chicago
Dates of operation	1961–present
Track gauge	4 ft 8 1⁄2 in (1,435 mm) standard gauge
Headquarters	Minneapolis, Minnesota

The Soo Line Railroad (reporting mark SOO) is the primary United States railroad subsidiary of the Canadian Pacific Railway (CP), controlled through the Soo Line Corporation, and one of seven U.S. Class I railroads. Although it is named for the Minneapolis, St. Paul and Sault Ste. Marie Railroad (MStP&SSM), which was commonly known as the Soo Line after the phonetic spelling of Sault, it was formed in 1961 by the consolidation of that company with two other CP subsidiaries, the Duluth, South Shore and Atlantic Railroad and Wisconsin Central Railroad. It is also the successor to other Class I railroads, including the Minneapolis, Northfield and Southern Railway (acquired 1982) and Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road, acquired at bankruptcy in 1985). On the other hand, a large amount of mileage was spun off in 1987 to Wisconsin Central Ltd., now part of the Canadian National Railway. The Soo Line and the Delaware and Hudson Railway, the CP's other major subsidiary (before the 2008 DM&E acquisition), presently do business as the Canadian Pacific Railway, and most equipment has been repainted into the CP's scheme, but the U.S. Surface Transportation Board groups all CP's U.S. subsidiaries under the Soo Line name for reporting purposes.