Firebox heating surface included 252 sq ft of thermic syphons (5) and arch tubes.
Worked the Hagerstown-Connellsville section, which has a 23-mile grade measured at 1.75%. M-2s showed a dynamometer rating of 4,700 drawbar horsepower at 50 mph, at which point it was indicating approx 35,000 lb of tractive effort. (The J-class 4-8-4s were not far behind at the higher speeds.) When worked on the descending grade of 0.3%, an M-2 could haul 8,000 tons of merchandise train, 10,500 tons of coal cars.
Bert Pennypacker notes (in Trains, April 1992) that the placement of the front truck directly under the smokebox was unusual. Other construction notes (from Pennypacker):
-- 3 Duplex thermic syphons in firebox, 2 in combustion chamber;
-- Standard HT automatic stoker;
-- Flexible staybolts in several points;
-- Type A superheater with American multi-valve throttle;
-- Hancock injector, Worthington feed-water heater, Barco low-water alarm.
Yet Pennypacker states that these engines were known as slippery and hard-to-handle brutes. He observes that the design (high drivers, light axle loads) wasn't really suitable for WM's style of heavy running.
| Specifications | |
|---|---|
| Class | M-2 |
| Locobase ID | 342 |
| Railroad | Western Maryland (WM) |
| Whyte | 4-6-6-4 |
| Road Numbers | 1201-1212 |
| Gauge | Std |
| Builder | Baldwin |
| Year | 1940 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase | 12' |
| Engine Wheelbase | 60.33' |
| Ratio of driving wheelbase to overall engine wheebase | 0.20 |
| Overall Wheelbase (engine & tender) | 106' |
| Axle Loading (Maximum Weight per Axle) | 67562 lbs |
| Weight on Drivers | 402266 lbs |
| Engine Weight | 601000 lbs |
| Tender Light Weight | 418950 lbs |
| Total Engine and Tender Weight | 1019950 lbs |
| Tender Water Capacity | 22000 gals |
| Tender Fuel Capacity (oil/coal) | 30 tons |
| Minimum weight per yard of rail on which locomotive could run | 111.74 lb rail |
| Geometry Relating to Tractive Effort | |
| Driver Diameter | 69" |
| Boiler Pressure | 250 psi |
| Cylinders (dia x stroke) | 22" x 32" (4) |
| Tractive Effort | 95397 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.22 |
| Heating Ability | |
| Firebox Area | 796 sq. ft |
| Grate Area | 118.80 sq. ft |
| Evaporative Heating Surface | 5770 |
| Superheating Surface | 1735 |
| Combined Heating Surface | 7505 |
| Evaporative Heating Surface/Cylinder Volume | 204.92 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 29700 |
| Same as above plus superheater percentage | 36566.02 |
| Same as above but substitute firebox area for grate area | 245004.66 |
| Power L1 | 25898.30 |
| Power MT | 851.61 |
| This page last modified: . | [Contact] | All material © 1999-2008 SteamLocomotive.com |