Chicago and Grand Trunk Railway

Grand Trunk Western Railroad

1887 map of Grand Trunk Railroad
Reporting mark	GTW
Locale	Michigan, Illinois, Indiana, Ohio
Dates of operation	1928–present
Track gauge	4 ft 8 1⁄2 in (1,435 mm) standard gauge
Headquarters	Detroit, Michigan

The Grand Trunk Western Railroad Company (reporting mark GTW) is an important American subsidiary of the Canadian National Railway (reporting mark CN) operating in Michigan, Illinois, Indiana and Ohio. Since a corporate restructuring in 1971 the railroad has been under CN's subsidiary holding company the Grand Trunk Corporation. Grand Trunk Western's routes are part of CN's Midwest Division. Its primary mainline between Chicago, Illinois, and Port Huron, Michigan, serves as a connection between railroad interchanges in Chicago and rail lines in eastern Canada and the Northeastern United States. The railroad's extensive trackage in Detroit and across southern Michigan has made it an essential link for the automotive industry as a hauler of parts and automobiles from manufacturing plants.

Grand Trunk Western grew out of a collection of rail lines which included:

Grand Trunk Western began as a route for the Grand Trunk Railway of Canada (GTR) to link its line to Chicago through lower Michigan. GTR's objective was to have a mainline from shipping ports in Portland, Maine to rail connections in Chicago through southern Ontario and Quebec that would serve Toronto and Montreal.