Japanese Government Railways classes D52 and C62
In World War II, Japan did not only have growing freight volumes, but also had to move lots of freight traffic from the sea onto the land as protection against attacks. So they designed the D52 that was a Mikado with a more powerful boiler and higher adhesive weight than the D51. The requirements included the use of a combustion chamber to increase power and measures to reduce the use of strategic materials. Train weights had to be 1,100 tonnes for regular freight trains and 1,200 tonnes for slower coal trains.
Five commercial builders completed 285 locomotives between 1943 and 1946. After freight traffic declined again after the war, 49 were rebuilt into 4-6-4 express locomotives in 1948 and 1949. These were designated C62 and used larger drivers with a diameter of 1,750 instead of 1,400 mm. They became the biggest and fastest passenger steam locomotives in Japan. In 1954, C62 17 set a speed record for narrow gauge steam locomotives in 129 km/h.
Both the original freight locomotives and the rebuilt express locomotives were used until the early seventies. The C62 even had to haul trains double-headed over a 2.5 percent incline on the Tōkaidō Main Line. After the D52 had been withdrawn between 1965 and 1973, six have been preserved. Of these, D52 70 is the only one that can move under its own power, although only on compressed air. After the last C62 had also been withdrawn in 1973, five had been preserved. C62 2 is the only one of these that is in working condition.
Technical data
General
| Property | D52 | rebuilt C62 |
|---|---|---|
| Built | 1943-1946 | 1948-1949 |
| Manufacturers | Kisha Seizō, Nippon Sharyō, Kawasaki, Hitachi, Mitsubishi | |
| Wheel arrangement | 2-8-2 (Mikado) | 4-6-4 (Hudson) |
| Gauge | 1,067 mm (Cape gauge) | |
Dimensions and weights
| Property | D52 | rebuilt C62 |
|---|---|---|
| Length | 21.11 m | 21.48 m |
| Empty mass | 74.4 t | |
| Service mass | 85.1 t | 88.8 t |
| Adhesion mass | 66.3 t | 48.2 t |
| Total mass | 136.9 t | 145.2 t |
| Axle load | 16.6 t | 16.1 t |
| Water capacity | 22,000 l | |
| Fuel capacity | 10 t (coal) | |
Boiler
| Property | D52 | rebuilt C62 |
|---|---|---|
| Grate area | 3.85 m² | |
| Firebox surface | 20.1 m² | |
| Tube heating surface | 147.7 m² | |
| Evaporative heating surface | 167.8 m² | |
| Superheater surface | 77.4 m² | |
| Total heating surface | 245.2 m² | |
Power plant
| Property | D52 | rebuilt C62 |
|---|---|---|
| Driver diameter | 1,400 mm | 1,750 mm |
| Boiler pressure | 16 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 550 x 660 mm | two, 520 x 660 mm |
Power
| Property | D52 | rebuilt C62 |
|---|---|---|
| Power source | steam | |
| Indicated power | 1,433 kW (1,948 PS) | 1,591 kW (2,163 PS) |
| Top speed | 85 km/h | 110 km/h |
| Starting effort | 193.9 kN | 138.7 kN |
Calculated values
| Property | D52 | rebuilt C62 |
|---|---|---|
| Factor of adhesion | 1 : 3.35 | 1 : 3.41 |
| Optimal speed | 45 km/h | 71 km/h |
| Power-to-weight ratio | 16.8 kW/t | 17.9 kW/t |
| Heating Surface Equivalent | 423.1 m² | |
| Cylinder volume/HSE | 1 : 741.22 | 1 : 662.56 |
| Adhesive weight/Total | 1 : 1.28 | 1 : 1.84 |
| Tractive force/Heating surface | 1 : 16.52 | 1 : 11.81 |
| Grate area/Heating surface | 1 : 63.69 | |
| Firebox/Tube surface | 1 : 7.35 | |
| Total/Superheater | 1 : 2.17 | |