Firebox heating surface included 153 sq ft in 4 thermic syphons in the firebox proper as well as in the combustion chamber. Known as "Potomacs," these engines had very nearly the same performance at 45 mph as the M-2 class 4-6-6-4s. They were the last 4-8-4s built new for a railroad in the US and retired with the rest of steam in 1954.
| Specifications | |
|---|---|
| Class | J-1 |
| Locobase ID | 286 |
| Railroad | Western Maryland (WM) |
| Whyte | 4-8-4 |
| Road Numbers | 1401-1412 |
| Gauge | Std |
| Builder | Baldwin |
| Year | 1947 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase | 19.25' |
| Engine Wheelbase | 46.83' |
| Ratio of driving wheelbase to overall engine wheebase | 0.41 |
| Overall Wheelbase (engine & tender) | 95' |
| Axle Loading (Maximum Weight per Axle) | 72500 lbs |
| Weight on Drivers | 290000 lbs |
| Engine Weight | 506500 lbs |
| Tender Light Weight | 421500 lbs |
| Total Engine and Tender Weight | 928000 lbs |
| Tender Water Capacity | 22000 gals |
| Tender Fuel Capacity (oil/coal) | 30 tons |
| Minimum weight per yard of rail on which locomotive could run | 120.83 lb rail |
| Geometry Relating to Tractive Effort | |
| Driver Diameter | 69" |
| Boiler Pressure | 255 psi |
| Cylinders (dia x stroke) | 26.5" x 32" |
| Tractive Effort | 70591 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.11 |
| Heating Ability | |
| Firebox Area | 573 sq. ft |
| Grate Area | 106.70 sq. ft |
| Evaporative Heating Surface | 4973 |
| Superheating Surface | 2170 |
| Combined Heating Surface | 7143 |
| Evaporative Heating Surface/Cylinder Volume | 243.44 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 27208.50 |
| Same as above plus superheater percentage | 35474.28 |
| Same as above but substitute firebox area for grate area | 190503.85 |
| Power L1 | 39288.30 |
| Power MT | 1194.70 |
| This page last modified: . | [Contact] | All material © 1999-2008 SteamLocomotive.com |