The JGR Class 9550 and the related Class 9580 were 2-8-0 Consolidation-type steam locomotives operated by the Japanese Government Railways from 1912 to 1949.
History[]
The Class 9550 was a fast freight locomotive used by the JGR. The type was ordered by the JGR in 1912, with a total of twenty-four locomotives manufactured by the Kawasaki Shipyards in two batches, the Class 9550 and the Class 9600 locomotives (no relation to the later class of locomotive); the Class 9600 locomotives were essentially identical to the Class 9550s but were equipped with a superheater, likely to exploit the fact they had purchased a patent for a Schmidt superheater. Prior to the completion of the later Class 9600 locomotives, the earlier Class 9600 locomotives were reclassified as Class 9580 locomotives and renumbered as such.
The locomotives were placed into service the same year and were immediately dogged with problems; even the superheated Class 9580s were dogged with problems as apparently the superheater tubes were arranged in a different way than what Schmidt had recommended. The locomotives were initially placed in the Eastern portions of Japan but were later moved all around, particularly in Kyushu and Hokkaido. The locomotives were largely disliked by crews and as a result suffered early retirements; all Class 9550 locomotives were retired by 1933 and all Class 9580s were retired by 1949. None were sold to the private sector after their retirement.
No Class 9550s survive and the locomotives are now considered a failure. However, they are now often thought of as a transitional prototype for the highly-successful superheated Class 9600 locomotives.