Grant was deeply involved in supplying the needs of the railroads in the late 1800s and early 1900s. As the Great Northern and other famous lines extended their tracks to the Pacific, Grant built depots, maintenance buildings and storage and service facilities all the way from Minnesota to Washington State. The largest of these projects, and one of the most famous, was St. Paul Union Depot. Constructed over a period of two years, it became one of St. Paul's most important buildings, and a visible symbol of its dominance as rail center for all the Northwest.