Data from Baldwin Locomotive Works, Record of Recent Construction ((1903), No. 39, p.268-269; and DeGolyer, Volume 25, p. 9. Works numbers were 20755-20756 in August 1902.
This pair of Americans was suited to the WM's mountainous profiles. The Baldwin specification included a note that reflects the constant battle to hold weight down while delivering capacity and strength: The railway "would prefer 9/16" [14.25 mm] boiler if weight can be kept down to 101,000 lb [45,813 kg]." Weight came up again in a note that said simply "Co does not want these engines to exceed 101,000 lb in working order." Apparently that wasn't possible, but Baldwin came close.
They served the line for 30 years before being scrapped in 1935 (52) and 1936 (51).
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | D-8 |
| Locobase ID | 10788 |
| Railroad | Western Maryland (WM) |
| Country | USA |
| Whyte | 4-4-0 |
| Number in Class | 2 |
| Road Numbers | 93-94/51-52 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Burnham, Williams & Co |
| Year | 1902 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 7.50 / 2.29 |
| Engine Wheelbase (ft / m) | 21.58 / 6.58 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.35 |
| Overall Wheelbase (engine & tender) (ft / m) | 45.75 / 13.94 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 67,165 / 30,466 |
| Engine Weight (lbs / kg) | 104,785 / 47,530 |
| Tender Loaded Weight (lbs / kg) | 65,215 / 29,581 |
| Total Engine and Tender Weight (lbs / kg) | 170,000 / 77,111 |
| Tender Water Capacity (gals / ML) | 3300 / 12.50 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 56 / 28 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 62 / 1575 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 24" / 457x610 |
| Tractive Effort (lbs / kg) | 19,189 / 8703.99 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.50 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 246 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 11.58 / 3.53 |
| Firebox Area (sq ft / m2) | 125 / 11.62 |
| Grate Area (sq ft / m2) | 29.24 / 2.72 |
| Evaporative Heating Surface (sq ft / m2) | 1606 / 149.26 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1606 / 149.26 |
| Evaporative Heating Surface/Cylinder Volume | 227.16 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 5263 |
| Same as above plus superheater percentage | 5263 |
| Same as above but substitute firebox area for grate area | 22,500 |
| Power L1 | 5869 |
| Power MT | 385.29 |