Sentetsu Tehosa-class locomotive

Chosen Government Railway Tehosa class (テホサ) Korean National Railroad Teou3 class (터우3) Korean State Railway Tŏusŏ class (더우서)
Builder's photo of a Tehosa-class locomotive.
Type and origin Power type Steam Builder ALCo, Gyeongseong Works Build date 1911, 1938 Total produced 9 (1911, ALCo), 1 (1938, Gyeongseong)
Specifications Configuration: ​  • Whyte 4-6-0 Gauge 1,435 mm (4 ft 8+1⁄2 in) Driver dia. 1,680 mm (66 in) Length 17,642 mm (57 ft 10.6 in) Width 2,821 mm (9 ft 3.1 in) Height 4,232 mm (13 ft 10.6 in) Loco weight 67.60 t (66.53 long tons) Tender weight 43.46 t (42.77 long tons) Fuel capacity 6.00 t (5.91 long tons) Water cap. 15,100 L (4,000 US gal) Firebox: ​  • Grate area 4.39 m2 (47.3 sq ft) Boiler: ​  • Small tubes 310 x 57 mm (2.2 in)  • Large tubes 24 x 137 mm (5.4 in) Boiler pressure 12.6 kgf/cm2 (179 psi) Heating surface: ​  • Firebox 12.00 m2 (129.2 sq ft)  • Tubes 158.80 m2 (1,709.3 sq ft)  • Total surface 170.80 m2 (1,838.5 sq ft) Superheater: ​  • Heating area 46.90 m2 (504.8 sq ft) Cylinders 1 Cylinder size 510 mm × 660 mm (20 in × 26 in) Valve gear Stephenson
Performance figures Maximum speed 95 km/h (59 mph) Tractive effort 111.0 kN (25,000 lbf)
Career Operators Chosen Government Railway Korean National Railroad Korean State Railway Class Sentetsu: テホサ KNR: 터우3 KSR: 더우서 Number in class 10 Numbers Sentetsu: テホサ1–テホサ10 Delivered 1911, 1938
Data for locomotives as rebuilt in the 1930s.

The Tehosa-class (テホサ) locomotives were a class of steam tender locomotives of the Chosen Government Railway (Sentetsu) with a 4-6-0 wheel arrangement.^[1] The "Teho" name came from the American naming system for steam locomotives, under which locomotives with 4-6-0 wheel arrangement were called "Ten Wheeler".^[2]

After the Liberation of Korea, of the 178 surviving locomotives of all Teho classes - including six previously owned by private railway companies - 106 went to the Korean National Railroad in the South, and 72 to the Korean State Railway in the North.^[3]

Whilst the first two classes of 4-6-0 locomotives in Korea, the Tehoi and Tehoni classes, were built by Baldwin, Sentetsu turned to a different American manufacturer for the third class - ALCo's Brooks Works^[4] built nine such locomotives for Sentetsu in 1911.^[1] Intended for long-range mixed trains, they were initially numbered 222–230, and subsequently were renumbered 651–659 in 1918. After being rebuilt with superheaters in the 1930s, they were redesignated テホサ (Tehosa) class and numbered テホサ1 through テホサ9 in the 1938 general renumbering.^[4] Like all Teho-type locomotives operated by Sentetsu, they had driving wheels of 1,680 mm (66 in) and a top speed of 95 km/h (59 mph),^[1] and many were assigned to the Manpo Line in the northern part of the country.^[1] One final unit, テホサ10, was built by Gyeongseong Works in 1938.^[4]

The exact dispersal of the ten Tehosa-class locomotives after the partition of Korea in 1945 and the division of Sentetsu assets in 1947 is uncertain, but at least two went to the South, where the Korean National Railroad designated them 터우3 (Teou3) class ^[1] and were used primarily on branchline trains.^[4]

Having been assigned primarily to the Manpo Line,^[1] most of the class went to the North after the partition, where they were designated 더우서 (Tŏusŏ) class by the Korean State Railway, but little is known of their service lives and subsequent fates.