New York, Susquehanna & Western becomes the first Class 1 railroad to embrace diesel technology. Other railroads are quick to follow.
The Chicago, Burlington & Quincy Railroad debuts Silver Dome, the first dome car, on its popular Chicago-Twin Cities Twin Zephyr.
General Motors' four-car, all-dome Train of Tomorrow, a product of its highly competitive Electro-Motive Division, is unveiled at Soldier Field in Chicago on May 28.
Alton Railroad becomes part of the Gulf, Mobile & Ohio.
Santa Fe's Chicago-to-Los Angeles Super Chief, successfully inaugurated in 1936 and streamlined in 1937, begins daily service.
New York Central fields the all-new Twentieth Century Limited; rival Pennsylvania Railroad counters with a new Broadway Limited.
Burlington, Rio Grande, and Western Pacific launch the Vista-Dome California Zephyr between Chicago and Oakland, California; however, for the first time in history, airline passenger-miles exceed those of the Pullman Company.
President Truman orders U.S. troops to the aid of South Korea.
Norfolk & Western's Roanoke Shops build the last steam locomotive in the United States, an 0-8-0 switcher.
Santa Fe is an early convert to diesel technology, partly due to the scarcity of water on its desert lines.
When an 0-6-0 switcher drops its fires at Camden, New jersey, the Pennsylvania Railroad is dieselized.
Grand Trunk Western pulls its Northerns out of local service in Michigan, putting an end to regularly scheduled passenger steam service in the United States.