Data from "Six-Coupled Tank Locomotive, Imperial Rys. of Japan," The Locomotive Magazine, Vol XV (15 February 1909), p. 39. Works numbers were 5175-5178.
To handle the Usui Toge incline was the mission of this rack locomotive design, a profile that required pulling 100-120 tons up a 1 in 40 grade (2 1/2%) on adhesion and 1 in 15 (6.7%) on the rack at 5 mph.. To negotiate the inevitably twisty alignment, the class was fitted with Cartazzi sliding boxes for both auxiliary axles.
In addition to its 15 1/2" x 20" cylinders for the adhesion system, it had 11 3/4" x 16" cylinders to operate the Abt rack system. The rack system lay in a frame built on the Lange & Livesey system, which was supported by the axle boxes of the second and thrid coupled axles.
BP had shipped 6 earlier 2-6-2RTs in two batches (works 4010-4013 in 1898 and 4311-4312 in 1902), but Locobase cannot say if they were built to the same design.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | unknown |
| Locobase ID | 10690 |
| Railroad | Imperial |
| Country | Japan |
| Whyte | 2-6-2RT |
| Number in Class | 4 |
| Road Numbers | |
| Gauge | 3'6" |
| Number Built | 4 |
| Builder | Beyer, Peacock |
| Year | 1908 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13 / 3.96 |
| Engine Wheelbase (ft / m) | 21.50 / 6.55 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.60 |
| Overall Wheelbase (engine & tender) (ft / m) | 21.50 / 6.55 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 86,016 / 39,016 |
| Engine Weight (lbs / kg) | 127,904 / 58,016 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 1824 / 6.91 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 36 / 914 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 15.5" x 20" / 394x508 |
| Tractive Effort (lbs / kg) | 20,421 / 9262.82 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.21 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 200 - 1.875" / 48 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | 87.70 / 8.15 |
| Grate Area (sq ft / m2) | 19.90 / 1.85 |
| Evaporative Heating Surface (sq ft / m2) | 1269 / 117.94 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1269 / 117.94 |
| Evaporative Heating Surface/Cylinder Volume | 290.53 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 3582 |
| Same as above plus superheater percentage | 3582 |
| Same as above but substitute firebox area for grate area | 15,786 |
| Power L1 | 4222 |
| Power MT | |