The RAG's report contains details that underscore just how specialized a design these unusual locomotives were. According to RAG, every effort was made to reduce weight in all the parts of the locomotive that weren't the boiler. Heat-treated steel and "high-grade" materials included Mayariu chromium-nickel steel made up the "main and side rods, driving and engine truck axles, main crosshead guides, piston-rod-extension guides, crosshead centers, pistons and piston rods, valve motion parts, and a number of minor parts" The Reading engineers used aluminum for a variety of components including main crosshead shoes, crosshead for piston-rod-extension, main steam valves, valve-stem crosshead, hand reversing wheel, cab window frames and smokebox door clips. Even the driving and engine truck axles had hollow cores.
According to the account, the resulting engine mounted "a larger boiler than any other passenger locomotive now in service on the Reading, while at the same time the total weight of the locomotive is less than that of some engines of other types now in heavy passenger service."
Piston valves measured 13" (336 mm) in diameter.
Certainly the four-point suspension (different from the typical "milking stool" three-point suspension usually used) contributed to the locomotives' failure as a type. The engines were rebuilt as Atlantics (class P7sa) within a year and renumbered 350-353 (see Locobase 9448) .
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Philadelphia & Reading|
|Number in Class||4|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.22|
|Overall Wheelbase (engine & tender)||63.12'|
|Axle Loading (Maximum Weight per Axle)||73100 lbs|
|Weight on Drivers||146200 lbs|
|Engine Weight||230800 lbs|
|Tender Light Weight||160000 lbs|
|Total Engine and Tender Weight||390800 lbs|
|Tender Water Capacity||8000 gals|
|Tender Fuel Capacity (oil/coal)||12 tons|
|Minimum weight of rail (calculated)||122 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||240 psi|
|Cylinders (dia x stroke)||23.5" x 26"|
|Tractive Effort||36614 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.99|
|Firebox Area||292 sq. ft|
|Grate Area||108 sq. ft|
|Evaporative Heating Surface||2491 sq. ft|
|Superheating Surface||679 sq. ft|
|Combined Heating Surface||3170 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||190.85|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||25920|
|Same as above plus superheater percentage||31363|
|Same as above but substitute firebox area for grate area||84797|