The Mantetsu records indicate that the engines were built at ALCo's Schenectady works, originally for the Boston & Maine Railroad.
Numbered 1 and 2 when first delivered, they were designated class H and renumbered 1000 and 1001 when Mantetsu introduced its second classification system in 1907.
After brief use on the mainline, they were reassigned to haul goods trains on the Anfeng Line in 1912.
In 1933, the Manchukuo National Railway was created through the nationalisation and merger of several privately owned railways, including the Jichang Jidun Railway, and these locomotives passed on to the Manchukuo National, which classified them Sorishi (ソリシ) class, numbered 6050 and 6051, becoming Soriro (ソリロ) 505 and 506 in 1938.
The Manchukuo National had eight other locomotives in the (1938) Soriro class, numbered ソリロ501–ソリロ504 and ソリロ507-510, but the origins of these engines is unknown; these were all sent to the Chosen Government Railway (Sentetsu) in Korea by 1942.