Originally designated class Б (B) by the CER, Baldwin in Philadelphia built fifty in 1898 (Б151-Б200), forty in 1899 (Б201-Б240), and a final batch of 31 in 1900 (Б241-Б271).

After the Japanese established the puppet state of Manchukuo, the Soviet Union sold its share of the North Manchuria Railway, as the CER had been renamed in 1932, to the new state's government on 23 March 1935,[2] It was then merged into the state-owned Manchukuo National Railway, which designated these locomotives ソリA (SoriA) class.

Not all of the CER's Х-class engines went to the MNR; some ended up in service in the USSR around Vladivostok.

In 2005, an X Locomotive was found buried in Lalin River, Jilin Province, China.

180, was excavated, restored, and is on display outside the Museum of the Imperial Palace of the Manchu State, Changchun.