Royal State Railways 4-6-2 Locomotives in Thailand
Class Details by Steve Llanso of Sweat House Media
Class 226 (Locobase 14260)
Data from narrowmind.railfan.net and elevation and photograph from Railways of Thailand as advertised at [
], supplemented by DeGolyer, Vol 78, pp. 394+, and Vol 79, pp. 470+. Works numbers were 58672-58675 in September 1925, 59436-59443 in August 1926, 60404-60411 in March 1928, 60900-60905 in July 1929.
This Pacific design shared its boiler and grate dimensions with the three-cylinder Mikados from the same year (Locobase 4413), but had a more conventional common stroke length for all three. Like those freight engines, the 4-6-2s were required to travel on 24.8 kg/metre (50 lb/yard) rails, grades of 2 1/2%, and manage relatively gentle 180 m/590 ft radii (9 3/4 degree) curves.
The 1928-1929 batches were delivered as wood burners, but could be converted easily to burn coal.
Four other Pacifics from Batignolles--222-225 in 1924-- and ten from Hitachi in 1941--283-292--were of very similar dimensions.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 226 |
| Locobase ID | 14260 |
| Railroad | Royal State Railways |
| Country | Thailand |
| Whyte | 4-6-2 |
| Number in Class | 26 |
| Road Numbers | 226-251 |
| Gauge | metre |
| Number Built | 26 |
| Builder | Baldwin |
| Year | 1925 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 9.50 / 2.90 |
| Engine Wheelbase (ft / m) | 27 / 8.23 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.35 |
| Overall Wheelbase (engine & tender) (ft / m) | 48.12 / 14.67 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 23,149 / 10,500 |
| Weight on Drivers (lbs / kg) | 69,005 / 31,300 |
| Engine Weight (lbs / kg) | 128,088 / 58,100 |
| Tender Loaded Weight (lbs / kg) | 70,647 / 32,045 |
| Total Engine and Tender Weight (lbs / kg) | 198,735 / 90,145 |
| Tender Water Capacity (gals / ML) | 3598 / 13.63 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 9.90 / 9 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 38 / 19 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 54 / 1372 |
| Boiler Pressure (psi / kPa) | 178.40 / 1230 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 15" x 20" / 381x508 (3) |
| Tractive Effort (lbs / kg) | 18,955 / 8597.85 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.64 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 120 - 2.008" / 51 |
| Flues (number - dia) (in / mm) | 18 - 5.236" / 133 |
| Flue/Tube length (ft / m) | 16.01 / 4.88 |
| Firebox Area (sq ft / m2) | 109.79 / 10.20 |
| Grate Area (sq ft / m2) | 33.15 / 3.08 |
| Evaporative Heating Surface (sq ft / m2) | 1518 / 141.03 |
| Superheating Surface (sq ft / m2) | 318 / 29.54 |
| Combined Heating Surface (sq ft / m2) | 1836 / 170.57 |
| Evaporative Heating Surface/Cylinder Volume | 247.40 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 5914 |
| Same as above plus superheater percentage | 6919 |
| Same as above but substitute firebox area for grate area | 22,916 |
| Power L1 | 12,898 |
| Power MT | 1236.22 |