Although the USA had already manufactured a small number of locomotives for the Allies before entering the Second World War, larger numbers were only built after the entry into the war. The S160 was created with features of existing Consolidations and was partly based on the Pershing from the First World War. It was dimensioned so that it could be used in large parts of Europe even on tracks that were in poor condition. It is noteworthy that the later used designation “S160” is nowhere to be found in the original documents from ALCO, Baldwin and Lima.

Typical simplifications of war locomotives were used in many places. The cheaper lubrication of the axle bearings led to many hot runners. Even more fatal was the use of a single type of water level indicator, previously unknown in Great Britain, which showed incorrect values if used incorrectly. This led to three boiler explosions in a short period of time. The tender was based on the British Austerity 2-8-0.

1,200 S160s were delivered to Wales and some were used in the preparations for D-Day. The rest was initially stored and only shipped to France after D-Day along with the others. From there they were distributed across Europe and the S160 was also used in the African war theater. Others were either delivered directly to other countries or arrived there later, so that ultimately the S160 could be found on all continents except Australia and Antarctica. A total of 2,120 were built, of which at least 26 remain today.