Data from P C Dewhurst, "The Jamaica Government Railway and its Locomotives", Locomotive Magazine, Volume 25 (15 September 1919), p. 154. Works numbers were3008-3009 in 1894.
The 18 was a single Rhode Island Locomotive Works 2-4-4T engine powered by simple-expansion cylinders (Locobase 20719).When the JGR went back to the Ocean State builder for more passenger tanks, wrote P C Dewhurst, the new locomotives were "practically a six-coupled compound enlargement of the 18." They arrived by sea at Montego Bay on Jamaica's northwest coast and were erected in those shops.
Alas, the pair was "not very satisfactory", had short careers, and thus were never reboilered. 22 suffered broken frames in 1899 and in 1905 and was scrapped in 1907. 21 was withdrawn from service in 1906 and scrapped in1908.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 21 |
| Locobase ID | 20721 |
| Railroad | West India Improvement Company (JGR) |
| Country | Jamaica |
| Whyte | 2-6-4T |
| Number in Class | 2 |
| Road Numbers | 21-22 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Rhode Island |
| Year | 1894 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13 / 3.96 |
| Engine Wheelbase (ft / m) | 30 / 9.14 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.43 |
| Overall Wheelbase (engine & tender) (ft / m) | 30 / 9.14 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 83,000 / 37,648 |
| Engine Weight (lbs / kg) | 129,500 / 58,740 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 2366 / 8.96 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 3.30 / 3 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 46 / 23 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 50 / 1270 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 24" / 457x610 (1) |
| Low Pressure Cylinders (dia x stroke) (in / mm) | 28" x 24" / 711x610 (1) |
| Tractive Effort (lbs / kg) | 16,837 / 7637.14 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.93 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 160 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 10 / 3.05 |
| Firebox Area (sq ft / m2) | 106 / 9.85 |
| Grate Area (sq ft / m2) | 17.60 / 1.64 |
| Evaporative Heating Surface (sq ft / m2) | 944 / 87.70 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 944 / 87.70 |
| Evaporative Heating Surface/Cylinder Volume | 267.10 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 3168 |
| Same as above plus superheater percentage | 3168 |
| Same as above but substitute firebox area for grate area | 19,080 |
| Power L1 | 2585 |
| Power MT | 205.99 |