Southern Railway Ps-4 class

In 1923, the Southern Railway began placing an order for new locomotives of the 4-6-2 Pacific design capable of handling up to fourteen cars over a moderate grade, as well as top speeds of 80 miles per hour (130 km/h).[3] The first group of locomotives were built by the American Locomotive Company at their Schenectady Works in that year, with twenty six delivered to the Southern, numbered 1366-1392; as well as five for the Cincinnati, New Orleans and Texas Pacific, numbered 6471-6475; and four for the Alabama Great Southern, numbered 6684-6687.[4] These locomotives were derived from the standard USRA Heavy Pacific design, but had notable differences based on the Southern's needs.[3] The Ps-4s had smaller driving wheels (73 inches vs. 79 inch USRA design), as well as larger, more spacious cabs, and featured single unit 3-B Worthington feedwater heaters under the left-hand running boards.[5]

In 1925, Southern Railway president Fairfax Harrison traveled to the United Kingdom, where he admired the country's London and North Eastern Railway's use of green-painted steam locomotives.[3] In 1926, Harrison's trip had inspired the appearance of the second order of Ps-4s, which was being built by ALCO's Richmond Works at the time.[3] These Ps-4s were painted in Sylvan green with gold leaf trimming and lettering.[3]

This order consisted of eleven locomotives for the Southern, numbered 1393-1404; seven for the Cincinnati, New Orleans and Texas Pacific, numbered 6476-6482; and four for the Alabama Great Southern, numbered 6688-6691.[6] Aside from the paint scheme, which would soon be applied to all of Southern's passenger locomotives, the second order had other notable differences.[6] They featured an Elesco feedwater heater rather than the Worthington heaters of the previous order, with the former placed on top of the smokebox between the stack and bell instead of under the running boards as the latter were placed.[6] The second order also had larger tenders better suited for long-distance passenger runs, with three-axle bogies and 14,000-gallon water capacity, versus the two-axle bogie, 10,000-gallon standard USRA tender design of the first order.[3]

The final Ps-4s were built in 1928 by the Baldwin Locomotive Works, consisting of only five engines for the Southern, numbered 1405-1409. These engines featured smaller tenders than the second order, but still larger than those of the first order, featuring two-axle bogies and a 12,000-gallon capacity. They also had Walschaerts valve gear instead of the Baker valve gear on previous orders. The final locomotive of the series, No. 1409, featured an extended smokebox with a Coffin feedwater heater.[6][7] This heater was fitted on an experimental basis and was later removed in favor of the Worthington heaters used in the first order.[8]

In 1941, No. 1380 was given bullet-nose streamlining designed by Otto Kuhler for use on the railway's Tennessean service, which operated between Washington, DC, and Monroe, Virginia, connecting in the latter to the Norfolk and Western Railway, who had assigned its streamlined J class engines to its connecting lines.[9][10] When the Tennessean was dieselized, No. 1380 joined the remainder of the Ps-4s assigned elsewhere on other express trains until it retired in 1953, though it retained its streamlining.[11]

The Ps-4 locomotives were assigned to many of the Southern's most famous passenger trains, including the Crescent, Piedmont Limited, Aiken-Augusta Special, and the Birmingham Special.[6] The Cincinnati, New Orleans and Texas Pacific assigned the engines to their Royal Palm, Ponce de Leon, Queen & Crescent, and Florida Sunbeam trains, among others.[6]

In 1941, the Southern began to retire the Ps-4s in favor of diesels. However, due to the onset of World War II, the railroad was unable to purchase additional diesel locomotives, and so opted to continue to employ the Ps-4s for the duration of the war. After the war, the railroad resumed dieselizing its trains, and the Ps-4s were largely out of service by 1948. Between 1949 and 1953, the Southern had scrapped all but one of the Ps-4s.[12]

Southern Railway Ps-4 No. 1401 on display at the National Museum of American History as part of the Smithsonian's "America on the Move" exhibition

The sole surviving Ps-4 is No. 1401 of the 1926 order, which was saved in 1953 by the railroad's outside legal counsel and later president Graham Claytor, who requested that the locomotive would be donated to the Smithsonian Institution.[13] In Summer 1961, No. 1401 was placed inside the Smithsonian's newly built National Museum of American History which opened in early 1964.[13] In June 1982, the American Society of Mechanical Engineers designated the locomotive as a Historic Mechanical Engineering Landmark.[14] Today, it currently remains on display at the museum.[15]

Wikimedia Commons has media related to Southern Railway class Ps-4.

• Steam Locomotive, Southern Railway 1401