Maryland & Pennsylvania 4-6-0 "Ten-wheeler" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 27 (Locobase 7052)

Data from M&PA 1956ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 29760 in December 1906 and 34945 in July 1910.

The Ma and Pa ordered these two Ten-wheelers almost 4 years apart. Specifications described a profile that included 2 1/2% grades and 25-degree curves.

Both were retired in 1955, the 28 first in August and the 27 in December.

Specifications by Steve Llanso of Sweat House Media
Locobase ID7052
RailroadMaryland & Pennsylvania (Ma & Pa)
Number in Class2
Road Numbers27-28
Number Built2
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft)12
Engine Wheelbase (ft)23.04
Ratio of driving wheelbase to overall engine wheebase 0.52
Overall Wheelbase (engine & tender) (ft)50.42
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)102,960
Engine Weight (lbs)128,860
Tender Loaded Weight (lbs)79,773
Total Engine and Tender Weight (lbs)208,633
Tender Water Capacity (gals)4000
Tender Fuel Capacity (oil/coal) (gals/tons)6
Minimum weight of rail (calculated) (lb/yd)57
Geometry Relating to Tractive Effort
Driver Diameter (in)56
Boiler Pressure (psi)180
High Pressure Cylinders (dia x stroke) (in)19" x 24"
Tractive Effort (lbs)23,671
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.35
Heating Ability
Firebox Area (sq ft)152
Grate Area (sq ft)25
Evaporative Heating Surface (sq ft)1920
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)1920
Evaporative Heating Surface/Cylinder Volume243.78
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4500
Same as above plus superheater percentage4500
Same as above but substitute firebox area for grate area27,360
Power L15717
Power MT367.24

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