These locomotives had 73" drivers, 23" x 28" cylinders, a 240 psi boiler pressure, a total weight of 312,590 lbs and a tractive effort of 41,300 lbs.
Data from 1934 Maine Central locomotive tables and MEC-PTC 4 -1956 Locomotive Diagrams supplied by Allen Stanley in May 2005 from his extensive Rail Data Exchange. See also DeGolyer, Volume 81, pp. 67+. (Thanks to Chris Hohl for his 26 February 2016 email adding the booster details.) Works numbers 61370-61371 in May 1930.
Pocket Hudsons, these were the lightest of the wheel arrangement. Their firebox heating surface included 14 sq ft (1.3 sq m) in two arch tubes and 74 sq ft (6.87 m) from two Nicholson thermic syphons. Piston valves measured 12" (305 mm) in diameter and reflected their "long-travel" description by shuttling 9" (229 mm) in each direction. The boiler also included a very high superheater surface area as a percentage of combined heating surface. The Franklin Type C-2-S boosters aided starting tractive effort. Drury (1993) argues that traffic and economic conditions explain a) why the Maine Central went with Hudsons in the first place, and b) why they only bought two. They served until 1950 (701) and 1955 (702); the last few years of 702 were spent on least to the Portland Terminal Company.
Principal Dimensions by Steve Llanso of Sweat House Media | |
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Class | D |
Locobase ID | 1044 |
Railroad | Maine Central (MEC) |
Country | USA |
Whyte | 4-6-4 |
Number in Class | 2 |
Road Numbers | 701-702 |
Gauge | Std |
Number Built | 2 |
Builder | Baldwin |
Year | 1930 |
Valve Gear | Baker |
Locomotive Length and Weight | |
Driver Wheelbase (ft / m) | 13 / 3.96 |
Engine Wheelbase (ft / m) | 35.67 / 10.87 |
Ratio of driving wheelbase to overall engine wheelbase | 0.36 |
Overall Wheelbase (engine & tender) (ft / m) | 72.37 / 22.06 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 57,600 / 26,127 |
Weight on Drivers (lbs / kg) | 171,400 / 77,746 |
Engine Weight (lbs / kg) | 312,590 / 141,789 |
Tender Loaded Weight (lbs / kg) | 189,610 / 86,006 |
Total Engine and Tender Weight (lbs / kg) | 502,200 / 227,795 |
Tender Water Capacity (gals / ML) | 10,000 / 37.88 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 14 / 13 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 95 / 47.50 |
Geometry Relating to Tractive Effort | |
Driver Diameter (in / mm) | 73 / 1854 |
Boiler Pressure (psi / kPa) | 240 / 16.50 |
High Pressure Cylinders (dia x stroke) (in / mm) | 23" x 28" / 584x711 |
Tractive Effort (lbs / kg) | 41,392 / 18775.12 |
Booster (lbs) | 12,200 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.14 |
Heating Ability | |
Tubes (number - dia) (in / mm) | 42 - 2.25" / 57 |
Flues (number - dia) (in / mm) | 166 - 3.5" / 89 |
Flue/Tube length (ft / m) | 20 / 6.10 |
Firebox Area (sq ft / m2) | 306 / 28.44 |
Grate Area (sq ft / m2) | 62.60 / 5.82 |
Evaporative Heating Surface (sq ft / m2) | 3826 / 355.58 |
Superheating Surface (sq ft / m2) | 1760 / 163.57 |
Combined Heating Surface (sq ft / m2) | 5586 / 519.15 |
Evaporative Heating Surface/Cylinder Volume | 284.25 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 15,024 |
Same as above plus superheater percentage | 19,832 |
Same as above but substitute firebox area for grate area | 96,941 |
Power L1 | 45,982 |
Power MT | 1774.32 |