The CGR played a vital role in Canada's wartime effort, moving vast numbers of troops and supplies.

[4] The Grand Trunk Pacific Railway (GTPR) was nationalized after defaulting on loan payments March 7, 1919, and entered the CNR fold on July 12, 1920.

GTPR's parent company, the bankrupt Grand Trunk Railway (GTR) was nationalized on May 21, 1920, and was absorbed into the CNR on January 30, 1923.

Large amounts of rolling stock were lettered for the CGR, although in many regions, such as the Maritimes, the public continued to refer to its trains and facilities by their old name of the Intercolonial.

A Privy Council order dated July 22, 1993, authorized the sale of CGR to the Crown corporation CN for one Canadian dollar.