USATC S160 Class

The United States Army Transportation Corps S160 Class is a class of 2-8-0 "Consolidation" type steam locomotives, designed for heavy freight work in Europe during World War II. A total of 2,120 were built and they worked on railroads across much of the world, including Africa, Asia, all of Europe and South America.

During the 1930s, the United States Army Transportation Corps approved an update of a Baldwin Locomotive Works World War I design, to be used, if required, for war transportation. The result was the S159 Class loco. During the early period of World War II, when America was neutral, the government of Franklin D. Roosevelt approved the Lend-Lease supply to the United Kingdom of the S200 Class, a 2-8-2 configuration, designed specifically to fit into the restricted British loading gauge.

With America's entry to World War II, the USATC needed a developed design from which a large number of locomotives could be constructed to run on the wrecked railways of Europe, deploying military hardware and civilian goods. Hence, the development of the S160 Class, designed by Maj. J. W. Marsh from the Railway Branch of the Corps of Engineers, which drew on previous locomotives, using austerity principles, and was built using methods which allowed for efficient and fast construction, and a long life, including axlebox grease lubricators, and rolled plates in preference to castings.

With cast frames (a few had frames which were flame-cut from rolled steel slabs) and cast wheels, the front two driving axles were sprung independently from the rear two driving axles, to cater for running on poor-quality track. The larger tender layout was derived from the similar design of the British WD Austerity 2-8-0, with an inset coal bunker above the water tank to improve visibility when running backwards.

800 locomotives were constructed in 1942/3 in thirteen batches, split between ALCO, Baldwin and Lima Locomotive Works. Shipped to South Wales and dispatched from the Great Western Railway locomotive depot at Ebbw Junction, Newport, the first 43 locomotives were transferred to the London & North Eastern Railway's Doncaster Works for completion, and later running in over the East Coast Main Line. This started a pattern whereby each of the four British railway companies eventually deployed a total of 400 S160's under the guise of "running in," but factually replacing damaged stock and increasing the capacity of the British railway system to allow for shipping of military pre-invasion equipment and troops. The eventual deployment of S160's were:

The second batch of 400 S160's were prepared for storage by USATC personnel at the Great Western's Ebbw Junction locomotive depot in the immediate run-up to D-Day. After the D-Day invasion of Normandy, the locomotives deployed across Britain again began to be collected and be refurbished at Ebbw Junction in preparation for shipment to Europe.

The S160's were designed for quick and efficient building, not long-term operations, thus compromises in design led to some difficulties in operation. The axle-box grease-lubricators were not very efficient, particularly when maintenance procedures lapsed or were delayed for operational war reasons, and so axle-boxes often ran hot. Braking was poor by modern standards, with a Westinghouse steam brake used for the locomotive, which was woefully insufficient, due to the long distance from the driver's valve to the brake cylinder.

A major fault of the S160 was use of a single water gauge of a Klinger design, unfamiliar to U.K. crews; it was necessary to open the top and bottom cocks slowly or the check valves would close, trapping water in the gauge and giving a false reading. If the valves were not fully open, the crews could be misled into thinking that the water level was adequate, even though it was becoming dangerously low. When a low water condition allowed the crown sheet to overheat, the stay bolts holding the crown sheet would fail with little warning, resulting in a boiler explosion. In a space of ten months, three UK S160s suffered a collapse of the firebox crown, with the first leading to the death of a GWR fireman on No. 2403 in November 1943. Although there are claims that the stay bolts or firebox design were less than for domestic locomotive boilers, the locomotives were equipped with a "boiler built to comply in all aspects with the A.S.M.E. Boiler Code, except that the shell shall have a factor safety of 4."