Maryland & Pennsylvania / York Southern 4-4-0 "American" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4-6 (Locobase 6023)

Data from George W. Fitch, Jr.'s compilation (Maryland and Pennsylvania Railroad Preservation and Historical Society photocopy reprint, 2004). Works numbers were 3287-3289)

A trio of eight-wheelers, these Americans were larger than the earlier Baldwin pair. They had shallower, radial-stay fireboxes; more tubes of shorter length, a shorter wheelbase, and larger tenders. The profile shows them to be typical Turn-of-the-Century locomotives.

#5 was retired in 1936 as worn out. #4 survived until March 1947. #6 received a superheater in May 1920, "Modern Steam Chest" in November 1923. It lasted the longest of the set, being retired only in November 1951.

Class WF Walworth (Locobase 6021)

Information from Maryland & Pennsylvania Preservation Society

History of the Ma & Pa ([], 7 May 2004). See also DeGolyer, Volume 20, p. 9. Works numbers were 14354 in July 1895 and 14547 in November

Originally built in narrow-gauge sections and first joined as the Maryland Central, the Ma & Pa, as it was later affectionally known, ran a twisting route from Baltimore to York, Pa. One of its components was the north-south Baltimore & Delta, which laid down tracks from Baltimore to Peach Bottom, Pa on the Susquehanna River in the late 1870s. The MC, which had laid tracks from York, Pa to Peach Bottom and explored southward toward Baltimore, bought the B & D in 1889. The MC in turn was purchased by the Baltimore & Lehigh, which struggled along until 1901, when it was bought by the Ma & Pa.

A series of amalgamations, bankruptcies, and other financial realignments eventually resulted in the Maryland & Pennsylvania in 1901. The Ma & Pa ran mail trains, milk trains, short-haul passenger (e.g., Bel Air to Baltimore), and freight. Much of the latter orginated in or near Delta, which had large slate quarries.

Over the years, the Ma & Pa gained outsized fame by offering railfan excursions. The operation's small, but robust operation and its proximity to major population centers ensured that its small stud of locomotives would appear in thousands of photographs.

Changes in traffic and the suspension of mail train subsidies led to the Ma & Pa's abandonment of passenger service in 1954. Freight service on the Pennsylvania District continued until the mid-1970s.

By the time of the Ma & Pa's incorporation in 1901, these typical eight-wheelers (Baldwin class 8-28-D-135) were part of the York Southern's contribution to the motive power roster.. Mixed-traffic locomotives, they operated for over 25 years, both being retired as "worn out, not worth repairing" on 30 June 1921 and December 1920, respectively.

Locomotive data from George W. Fitch, Jr.'s compilation (Maryland and Pennsylvania Railroad Preservation and Historical Society photocopy reprint, 2004).

NB: Baltimore, Chesapeake & Atlantic's #8 and 9 were Baldwin's. These seem to have been identical to the York Southern engine shown here, but the Baldwin spec doesn't show the heating surface data.

Principal Dimensions by Steve Llanso of Sweat House Media
Class4-6WF Walworth
Locobase ID6023 6021
RailroadMaryland & Pennsylvania (Ma & Pa)York Southern (Ma & Pa)
Number in Class32
Road Numbers4-61, 3
Number Built32
BuilderRichmondBurnham, Williams & Co
Valve GearRichardson BalancedStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.50 / 2.29 8.50 / 2.59
Engine Wheelbase (ft / m)20.50 / 6.2522.67 / 6.91
Ratio of driving wheelbase to overall engine wheebase 0.37 0.37
Overall Wheelbase (engine & tender) (ft / m)46.54 / 14.1945.92 / 14
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)67,100 / 30,43650,940 / 23,106
Engine Weight (lbs / kg)101,300 / 45,94980,540 / 36,532
Tender Loaded Weight (lbs / kg)81,800 / 37,10466,940 / 30,364
Total Engine and Tender Weight (lbs / kg)183,100 / 83,053147,480 / 66,896
Tender Water Capacity (gals / ML)4000 / 15.153000 / 11.36
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)6 / 5.506 / 5.50
Minimum weight of rail (calculated) (lb/yd / kg/m)56 / 2842 / 21
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)62 / 157562 / 1575
Boiler Pressure (psi / kPa)180 / 12.40160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x61016" x 24" / 406x610
Tractive Effort (lbs / kg)17,116 / 7763.7013,477 / 6113.07
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.92 3.78
Heating Ability
Firebox Area (sq ft / m2)92.65 / 8.6198.59 / 9.16
Grate Area (sq ft / m2)20.54 / 1.9116.50 / 1.53
Evaporative Heating Surface (sq ft / m2)1235 / 114.781146 / 106.51
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1235 / 114.781146 / 106.51
Evaporative Heating Surface/Cylinder Volume195.88205.19
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation36972640
Same as above plus superheater percentage36972640
Same as above but substitute firebox area for grate area16,67715,774
Power L150104852
Power MT329.21419.98

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