Data from M&PA 1956ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volumes 29, p. 209 and 35, pp. 296+. Works numbers were 29760 in December 1906 and 34945 in July 1910.
The Ma and Pa ordered these two Ten-wheelers almost four years apart. Specifications described a profile that included 2 1/2% grades and 25-degree curves. All of the specs for the 28 repeated those for the 27 to the last jot and tittle--even the details about how the tubes were to be swaged down to 2" diameter.
Both were retired in 1955, the 28 first in August and the 27 in December.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 27 |
| Locobase ID | 7052 |
| Railroad | Maryland & Pennsylvania (Ma & Pa) |
| Country | USA |
| Whyte | 4-6-0 |
| Number in Class | 2 |
| Road Numbers | 27-28 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Burnham, Williams & Co |
| Year | 1906 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 12 / 3.66 |
| Engine Wheelbase (ft / m) | 23.04 / 7.02 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.52 |
| Overall Wheelbase (engine & tender) (ft / m) | 50.42 / 15.37 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 102,960 / 46,702 |
| Engine Weight (lbs / kg) | 128,860 / 58,450 |
| Tender Loaded Weight (lbs / kg) | 79,773 / 36,184 |
| Total Engine and Tender Weight (lbs / kg) | 208,633 / 94,634 |
| Tender Water Capacity (gals / ML) | 4000 / 15.15 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 6 / 6 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 57 / 28.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 56 / 1422 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 19" x 24" / 483x610 |
| Tractive Effort (lbs / kg) | 23,671 / 10737.00 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.35 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 228 - 2.25" / 57 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 13.25 / 4.04 |
| Firebox Area (sq ft / m2) | 152 / 14.13 |
| Grate Area (sq ft / m2) | 25 / 2.32 |
| Evaporative Heating Surface (sq ft / m2) | 1920 / 178.44 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1920 / 178.44 |
| Evaporative Heating Surface/Cylinder Volume | 243.65 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 4500 |
| Same as above plus superheater percentage | 4500 |
| Same as above but substitute firebox area for grate area | 27,360 |
| Power L1 | 5714 |
| Power MT | 367.05 |