JNR Class D50

The Class D50 is a type of 2-8-2 steam locomotive built by the Japanese Government Railways (JGR), the Japanese National Railways (JNR) and various manufacturers from 1923 to 1931. The class name indicates that the locomotive has four sets of driving wheels (D) and belongs to one of the classes of tender locomotive allocated a number in the series 50 to 99 in the Japan Railways locomotive numbering and classification scheme of 1928. Hideo Shima designed the rest of the class until 1931.

Japanese National Ry Class D50 China Railways 解放16 class
D50 319 in 1935
Type and origin Power type Steam Designer Tokichi Ogasawara and Hideo Shima Builder Kawasaki (204) Hitachi (80) Kisha Seizō (69) Nippon Sharyō (27) Build date 1923–1931 Total produced 380
Specifications Configuration: ​  • Whyte 2-8-2  • UIC 1′D1′ h2 Gauge 1,067 mm (3 ft 6 in) Driver dia. 1,400 mm (55.12 in) Length 17,248 mm (56 ft 7 in) Height 3,955 mm (12 ft 11+3⁄4 in) Axle load 14.70 tonnes (14.47 long tons; 16.20 short tons) Loco weight 78.14 tonnes (76.91 long tons; 86.13 short tons) Tender weight 49 tonnes (48 long tons; 54 short tons) Firebox: ​  • Grate area 3.25 m2 (35.0 sq ft) Boiler: ​  • Tube plates 5,500 millimetres (18 ft 1⁄2 in)  • Small tubes 57 mm (2+1⁄4 in), 90 off  • Large tubes 140 mm (5+1⁄2 in), 28 off Boiler pressure 13.0 kg/cm2 (1.27 MPa; 185 psi) Heating surface: ​  • Firebox 13.5 m2 (145 sq ft)  • Tubes and flues 142.7 m2 (1,536 sq ft) Superheater: ​  • Heating area 64.4 m2 (693 sq ft) Cylinders Two, outside Cylinder size 570 mm × 660 mm (22+7⁄16 in × 26 in)
Performance figures Maximum speed 70 km/h (43 mph) Tractive effort 165.977 kN (37,313 lbf)
Career Operators Japanese Government Railways Japanese National Railways Jichang Jidun Railway Manchukuo National Railway Central China Railway China Railway Class JGR: 9900 → D50 JNR: D50 CCR: D50 CR: ㄇㄎ16 → 解放16 Numbers D50 1-D50 380 (formerly 9900-9999,19900-19999,29900-29975) Retired 1965 Preserved D50 25, D50 140 Disposition Two preserved, remainder scrapped

The design of the D50 was based on the JNR Class 9600 which was introduced in 1916. A total of 380 Class D50 locomotives were built. Between 1951 and 1956 78 were rebuilt to JNR Class D60 2-8-4 Berkshire’s by the JNR. This class would later form the JNR Class D51.

Service in China

Manchukuo National Railway

Main article: China Railways JF5

In 1923, sixteen D50 class locomotives were exported to the Jichang Jidun Railway in Manchuria, which designated them class 500 and numbered 501 through 516. Ten were built by Kawasaki (works nos. 970−971, 1140−1170) and six by Kisha Seizō (w/n 965−970), and though very similar to the Japanese D50 class, there were some slight differences in dimensions due to the larger loading gauge on Chinese lines. After the establishment of Manchukuo, the Jichang Jidun Railway was nationalised along with other private railways to form the Manchukuo National Railway. The MNR classified these Mikana (ミカナ) class, numbered 6540−6555, renumbered 501−516 in 1938. After the establishment of the People's Republic of China, China Railways designated them ㄇㄎ₅ (MK₅) class in 1951, and subsequently 解放₅ (JF₅) class in 1959.

Central China Railway

In 1939, D50 193 was converted to standard gauge and shipped to the Central China Railway, where it operated primarily between Nanjing and Shanghai. This engine lasted in service on China Railways until 1955.

China Railways

After the establishment of the People's Republic of China, all the railways of China were taken over by the China Railway, which classified the D50s as ㄇㄎ₁₆ (MK₁₆) class in 1951, later becoming class 解放₁₆(JF₁₆).

Preserved examples

Two D50s are preserved in Japan.

• D50 25: In a park in Kitami, Hokkaido
• D50 140: At the Kyoto Railway Museum

• 
  D50 25 in Kitami, Hokkaido
• 
  D50 140 at Umekoji Steam Locomotive Museum

See also

• Japan Railways locomotive numbering and classification
• JNR Class 9600
• JNR Class D51
• JNR Class D52
• JNR Class D60
• JNR Class D61
• JNR Class D62