Cumberland Valley 2-2-2 "Single" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class Pioneer (Locobase 5038)

A rare wheel arrangement for any nation, but especially so for North America. Pioneer and Jenny Lind may have already entered service in Connecticut when the CVRR obtained them. In any event, they were seen to be the answer to a requirement for a light-traffic locomotive that would reduce the deadweight to passenger ratio.( The railroad ran from Winchester, Va in the Shenandoah Valley to Harrisburg, Pa.) Boston and Enterprise were built to similar specs by Wilmarth in 1854-1855.

During the 1850s, the class indeed filled the bill, according to John H White's Smithsonian Institution Monograph. Under the right conditions, a Pioneer could pull a four-car passenger train at speeds up to 40 mph (64 kph). Pioneer herself averaged over 20,000 miles per year in that decade. After the Civil War, which had affected the CVRR severely, the Pioneer had one more year of 20,546 miles turned, but increasing train weights soon relegated her to work trains and then to storage. Fortunately, her status as a pioneer led to preservation for commemorative events and ultimately to her donation to the Smithsonian.

Construction details include a deep, wood-burning firebox, copper tubes and tube sheet (although these were later replaced by iron), a dome boiler with steam dome over the firebox, large, vase-shaped bonnet stack with spark-arresting features, a sandwich-type frame.

Boiler pressure is an estimate based on other engines of the time. Heating surface is calculated based on the number of tubes, their diameter, and length added to which was the reported firebox heating surface area.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID5038
RailroadCumberland Valley
Number in Class4
Road Numbers13
Number Built4
BuilderSeth Wilmarth
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)13.59 / 4.14
Ratio of driving wheelbase to overall engine wheebase
Overall Wheelbase (engine & tender) (ft / m)13.59 / 4.14
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)
Engine Weight (lbs / kg)25,000 / 11,340
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)25,000
Tender Water Capacity (gals / ML)600 / 2.27
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 1372
Boiler Pressure (psi / kPa)100 / 6.90
High Pressure Cylinders (dia x stroke) (in / mm)8.5" x 14" / 216x356
Tractive Effort (lbs / kg)1592 / 722.12
Factor of Adhesion (Weight on Drivers/Tractive Effort)
Heating Ability
Firebox Area (sq ft / m2)41.05 / 3.82
Grate Area (sq ft / m2) 5.25 / 0.49
Evaporative Heating Surface (sq ft / m2)260 / 24.16
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)260 / 24.16
Evaporative Heating Surface/Cylinder Volume282.77
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation525
Same as above plus superheater percentage525
Same as above but substitute firebox area for grate area4105
Power L14554
Power MT

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Wes Barris