Speedy Pacifics that proved to be a bit light. Baldwin built five, Richmond turned out seventeen. The first 91 and 93 destroyed each other in a head-on collision on 19 November 1912, killing six people. They were replaced by two engines in 1913.
Firebox heating surface includes 24.2 sq ft (2.25 sq m) of arch tubes. 12" (305 mm) diameter piston valves supplied steam to the cylinders. The locomotives had modified Hodges trailing trucks with an arrangement of swings, links, and equalizers that reduced "to a large extent, any tendency to throw the spring out of alignment with the truck frame when the locomotive is curving."
Later increases in tender capacity to 15 tons (13.6 tonnes) of coal and 9,000 US gallons (34,065 litres) of water resulted in a loaded tender weight of 151,640 lb (79,061 kg). The larger tender extended the engine-and-tender length to 66 ft 3 in (21.9 m). The last
At least the 865, 867, and 868 were shrouded in streamliner casings that resembled those of the Milwaukee Road's A-class Atlantics. The color scheme was a dark green overall decorated with a broad gold band near the top and thin yellow and red stripes just below the footboard.
Most of the class operated through World War II and were retired in the late 1940s. The last two -- 858 and 862--were scrapped in November 1951.
Locobase had estimated the superheater area, which was not given in the diagrams, as 540 sq ft based on similar installations in other locomotives. The 1918 diagrams gave the superheater area as 638 sq ft (59.27 sq m).
Firebox heating surface includes 24.2 sq ft (2.25 sq m) of arch tubes. These fast-freight Pacifics had the same driver diameter as the Mikados. R&ER's report noted that the "freight locomotives are well proportioned to meet conditions on a line which, like the Seaboard, is free from excessive grades and handles large quantities of perishable materials at fairly high speeds." Thirteen-inch diameter (330 mm) piston valves admitted steam to the cylinders. Although the specification gave 180 psi, boiler pressure was described as 185 psi (12.76 bar) only a few months after its delivery.
The Baldwin estimates for tender weight came close to the actual figure given in the 1913 report on their service entry on the Seaboard. The 1918 diagrams show several clear differences from either the Baldwin specs or the 1913 story. Superheater area for the same superheater installation is given as 638 sq ft (59.73 sq m). Locobase hasn't quite deduced the reason for the 63 sq ft difference. Weight on the drivers increased to 144,500 lb (65,544 kg) and engine weight grew to 220,000 lb (99,790 kg). Loaded tender weight (same capacity as delivered) now came to 151,640 lb (68,783 kg).
See Locobase 8748 for the P-1/P-2 69" drivered passenger variant.
Although the first fifteen locomotives of this design were delivered as P-1 mixed-traffic engines with 63" drivers (Locobase 1400), most were completed as 69"-drivered passenger engines. They were delivered with the same cylinder volume, but later saw a 1" (25.4 mm) increase in diameter, presumably to compensate for the taller drivers.
Firebox heating surface includes 26 sq ft (2.4 sq m) of arch tubes and steam was admitted through 13" (330 mm) piston valves.
Other than the 832, which suffered a head-on collision with Mountain 220 near Stark Florida in a December 1931 wreck, the entire class served the SAL throughout World War II before being cut up in the late 1940s, early 1950s.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Seaboard Air Line (SAL)||Seaboard Air Line (SAL)||Seaboard Air Line (SAL)|
|Number in Class||20||15||35|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||12.50 / 3.81||12.50 / 3.81||12.50 / 3.81|
|Engine Wheelbase (ft / m)||32.75 / 9.98||32.75 / 9.98||32.75 / 9.98|
|Ratio of driving wheelbase to overall engine wheebase||0.38||0.38||0.38|
|Overall Wheelbase (engine & tender) (ft / m)||66.25 / 20.19||62.89 / 19.17||62.89 / 19.17|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||48,200 / 21,863||49,600 / 22,498||52,164 / 23,661|
|Weight on Drivers (lbs / kg)||137,700 / 62,460||133,900 / 60,736||148,690 / 67,445|
|Engine Weight (lbs / kg)||214,700 / 97,386||211,600 / 95,980||230,600 / 104,599|
|Tender Loaded Weight (lbs / kg)||147,000 / 66,678||148,400 / 67,313||174,300 / 79,061|
|Total Engine and Tender Weight (lbs / kg)||361,700 / 164,064||360,000 / 163,293||404,900 / 183,660|
|Tender Water Capacity (gals / ML)||8000 / 30.30||8000 / 30.30||9000 / 34.09|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||14 / 12.70||14 / 12.70||15 / 13.60|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||77 / 38.50||74 / 37||83 / 41.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||72 / 1829||63 / 1600||69 / 1753|
|Boiler Pressure (psi / kPa)||195 / 13.40||185 / 12.80||180 / 12.40|
|High Pressure Cylinders (dia x stroke) (in / mm)||23" x 28" / 584x711||22" x 28" / 559x711||22" x 28" / 559x711|
|Tractive Effort (lbs / kg)||34,098 / 15466.61||33,826 / 15343.23||30,050 / 13630.47|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.04||3.96||4.95|
|Firebox Area (sq ft / m2)||210 / 19.51||208.20 / 19.34||210 / 19.51|
|Grate Area (sq ft / m2)||53.10 / 4.93||53.10 / 4.93||53.10 / 4.93|
|Evaporative Heating Surface (sq ft / m2)||2820 / 261.98||2820 / 261.98||2820 / 261.98|
|Superheating Surface (sq ft / m2)||575 / 53.42||575 / 53.42||540 / 50.17|
|Combined Heating Surface (sq ft / m2)||3395 / 315.40||3395 / 315.40||3360 / 312.15|
|Evaporative Heating Surface/Cylinder Volume||209.44||228.91||228.91|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||10,355||9824||9558|
|Same as above plus superheater percentage||12,115||11,493||11,087|
|Same as above but substitute firebox area for grate area||47,912||45,065||43,848|