Southern Railway 1401 is a 4-6-2 steam locomotive built in July 1926 by American Locomotive Company (ALCO) of Richmond, Virginia, for the Southern Railway (SOU) as a member of the Ps-4 class, which was based on the United States Railroad Administration (USRA) Heavy Pacific design with some minor differences.

1401 was donated to the National Museum of American History in Washington, D.C., around 1961, where it remains on permanent display as the sole survivor of the Southern Railway Ps-4 class.

During the 1920s, the Southern Railway's (SOU) roster consisted of smaller Ps-2 class 4-6-2 Light Pacifics that could not handle the longer and heavier mainline passenger trains between Washington, D.C., and Atlanta, Georgia.

1366–1392, built between 1923 and 1924 by the American Locomotive Company (ALCO) of Schenectady, New York, and were originally painted black with golden yellow linings and lettering.

[7][a] The Ps-4s were based on the United States Railroad Administration (USRA) Heavy Pacific design, differing in that they lacked the smaller 73 in (1.854 m) driving wheels, and included a slightly shorter boiler, an additional firebox combustion chamber, and a Worthington 3-B type feedwater heater.

[3][10] These arrangements made the Ps-4s produce 47,535 lbf (211.45 kN) of tractive effort, which allowed them to pull 14 passenger cars at 80 mph (129 km/h) on SOU's Piedmont terrain.

[3][10] During 1925, SOU president Fairfax Harrison traveled to the United Kingdom where he admired the country's London and North Eastern Railway's (LNER) apple-green Gresley A1-class locomotives, which inspired him to repaint the Ps-4s and the SOU's other passenger locomotives in a new Virginian green and gold paint scheme.

[3][b] Because of the Ps-4s' glamorous Virginian green and gold paint scheme, they were signified as the First Ladies of the Pacifics around the SOU system.

1366–1404 were eventually re-equipped with Walschaerts valve gears in the mid-late 1930s as the SOU mechanical officers were concerned for the Baker type risking to reverse itself at high-speed and could easily damage the locomotive's wheels and the rails.

[21][25][26] Additionally, the Ps-4s were in motive power pool service, where they were called in to pull SOU's mainline passenger trains again whenever one of the diesel locomotives was unavailable.

1401 locomotive was retired after it finished its last revenue run on SOU's Danville Division between Salisbury and Monroe, Virginia.

1401 locomotive was chosen for preservation and was towed to Alexandria, Virginia, to be stored at the Henry Street Yard to await the Smithsonian's decision.

1401 was given a visor on its headlight and the "Charlotte" Division logo inscribed underneath its cab per advice of W. Graham Claytor Jr., who was SOU president at the time.