Data from John H White Jr, American Single Locomotives and the "Pioneer", Smithsonian Studdies in History and Technology, Number 25 (Washington, DC: Smithsonian Institution Press, 1973).( Thanks to Chris Hohl for this 21 June 2024 email noting the tender's fuel capacity.)
A rare wheel arrangement for a North American railroad and a frame on which all three axle had no lateral movement rendered it even more unusual. 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. In addition to 600 US gallons (2,271 litres), the Pioneer's tender carried one cord of wood.
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 Middle Run Media | |
|---|---|
| Class | Pioneer |
| Locobase ID | 5038 |
| Railroad | Cumberland Valley |
| Country | USA |
| Whyte | 2-2-2T |
| Number in Class | 4 |
| Road Numbers | 13 |
| Gauge | Std |
| Number Built | 4 |
| Builder | Seth Wilmarth |
| Year | 1851 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | |
| Engine Wheelbase (ft / m) | 13.59 / 4.14 |
| Ratio of driving wheelbase to overall engine wheelbase | |
| 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 / Liters/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 / 690 |
| 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 | |
| Tubes (number - dia) (in / mm) | 63 - 1.875" / 48 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 7.08 / 2.16 |
| Firebox Area (sq ft / m2) | 41.05 / 3.81 |
| Grate Area (sq ft / m2) | 5.25 / 0.49 |
| Evaporative Heating Surface (sq ft / m2) | 260 / 24.15 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 260 / 24.15 |
| Evaporative Heating Surface/Cylinder Volume | 282.61 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 525 |
| Same as above plus superheater percentage | 525 |
| Same as above but substitute firebox area for grate area | 4105 |
| Power L1 | 4551 |
| Power MT | |