China Railways TH1

In 1908, Mantetsu ordered seventeen locomotives from ALCo in the United States for express and ordinary passenger train duties on the mainline. Built at ALCo's Schenectady works and designated class F1, from 1911 they were used also on express trains on the Dalian–Lüshun line, and on the Anfeng Line between Fengtian and Andong. With the introduction of a new classification system in 1920 they became class Tehoi (テホイ), and between then and 1926 they were rebuilt with superheaters. In 1927, one engine was leased to the Sitao Railway, which in 1933 was nationalised along with several other private railways to create the Manchukuo National Railway, and in the same year, four were transferred to the Fushun Coal Mine, which was under Mantetsu's control. In 1931 three of the locomotives sent to Fushun were returned in exchange for a Sorii class engine, and in that year some were loaned to the Jinfu Railway. With the establishment of the Manchukuo National Railway in 1933, two were transferred to the MNR, where they were designated Tehosa (テホサ) class.

After the reconstruction of the Anfeng Line in 1911, a thrice-weekly international express train between Fengtian and Gyeongseong, Korea was introduced. As the existing locomotives insufficient in quantity, Mantetsu ordered five new engines from ALCo in 1912 to augment the fleet. Built at ALCO's Richmond, Virginia plant, they were designated class F1 like the 1908 units, though they were not identical to those, and in the 1920 reclassification they became Tehoni (テホニ) class. Between 1920 and 1926 they were rebuilt with superheaters. Used on both express and ordinary passenger trains, some were loaned to the Jinfu Railway in 1931.

Under the new unified classification system introduced in 1938, the Mantetsu Tehoi class, the Mantetsu Tehoni class, and the Manchukuo National Tehosa class locomotives were collectively designated Tehoi class.