Pennsylvania 2-4-6 Locomotives in the USA
Class Details by Steve Llanso of Sweat House Media
Class Old L/"Jumbo" (Locobase 5489)
Data from [
] (Viewed 11 April 2003). See also the Christopher T Baer, "A General Chronology Of The Pennsylvania Railroad Company, Its Predecessors And Successors and Its Historical Context -- 1882", Pennsylvania Railroad Historical Society, last updated November 2015, archived online at [
], last accessed 12 January 2018. (Thanks to Chris Hohl for his 3 January 2018 email noting the L's road number.). Works number was 645 in 1882.
According to William Edson's exhaustive compilation, this locomotive was designed by Theodore N. Ely. The arrangement looks very much like a Mason Bogie suburban tank engine. 2-4-6Ts (56-60, 1883) ran on the Long Island Railroad, but these were quite a bit smaller. The firebox on the L class was shallow, narrow and long with a sharply sloped backhead--all characteristics of the Altoona boiler. Tube length was exceptional for the time as well, only rivalled the Santa Fe 4-8-0s shown in Locobase 8996.
The L's nickname came from its then great size and reflected the recent arrival of P T Barnum's enormous elephant and its immediate adoption as a template for largeness.
The Jumbo only operated for about 11 years and was scrapped in October 1893
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Old L/"Jumbo" |
| Locobase ID | 5489 |
| Railroad | Pennsylvania (PRR) |
| Country | USA |
| Whyte | 2-4-6T |
| Number in Class | 1 |
| Road Numbers | 4 |
| Gauge | Std |
| Number Built | 1 |
| Builder | Altoona |
| Year | 1882 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 7 / 2.13 |
| Engine Wheelbase (ft / m) | 31.33 / 9.55 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.22 |
| Overall Wheelbase (engine & tender) (ft / m) | 31.33 / 9.55 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 32,500 / 14,742 |
| Weight on Drivers (lbs / kg) | 59,750 / 27,102 |
| Engine Weight (lbs / kg) | 124,100 / 56,291 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 124,100 |
| Tender Water Capacity (gals / ML) | 1680 / 6.36 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.50 / 1 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 50 / 25 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 62 / 1575 |
| Boiler Pressure (psi / kPa) | 125 / 860 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 17" x 24" / 432x610 |
| Tractive Effort (lbs / kg) | 11,886 / 5391.41 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.03 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 171 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 14.94 / 4.55 |
| Firebox Area (sq ft / m2) | |
| Grate Area (sq ft / m2) | 21.05 / 1.96 |
| Evaporative Heating Surface (sq ft / m2) | |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | |
| Evaporative Heating Surface/Cylinder Volume | |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2631 |
| Same as above plus superheater percentage | 2631 |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |