Locobase 7113 shows the original configuration of the first RF & P Pacifics. In the 1920s, a few were substantially made over. Cylinder diameter grew by an inch, 24 flues holding a useful amount of superheater area took the place of 130 tubes and the firebox heating surface grew with the addition of 53 sq ft of thermic syphons.
This class left service over a 17-year period beginning in 1929.
The first of the many classes of Pacifics used by this passenger bridge road, the 80s (Locobase 5694), now renumbered in the 201 series, were taken in hand and superheated in 1921. The new arrangement included 29 sq ft of arch tubes in the firebox and a tube-flue distribution that retained virtually all of the evaporative heating surface while adding a useful percentage of superheater elements.
http://www.railarchive.net/alcopacifics/index.html (accessed 16 June 2006).
Light Pacific built with superheaters. As delivered, they had 22"-diameter cylinders and 190 sq ft of firebox heating surface. Compared to most North American Pacifics then or later, this design had quite a lot of evaporative heating surface for the cylinders it fed.
A later updating enlarged the direct heating area by including 29 sq ft of arch tubes and 62 sq ft of thermic syphons in the firebox heating surface. The RF & P also increased cylinder diameter by 1".
Data from DeGolyer, Vol 74, pp.176+ suggests that this is was the engine to which Partington referred. The class was produced for the RF & P from 1918 to 1925. Alco delivered 301-306 under order R-265 in 1918 and followed with 2 more under order R-293 in 1920. Baldwin's four had works numbers 57587-57588 in December 1923 and 58795-58796 in October 1925.
They were essentially repeats of the earlier 401 (Locobase 1390), but with much taller drivers. Thus, although they resemble the USRA engines in some particulars, this group of locomotives were independently procured. They had 14" (356 mm) piston valves.
As built, the firebox heating surface amounted to 259.6 sq ft, of which 25.6 sq ft was arch tubes. Some time later, the railroad revised the firebox layout; see Locobase 6679.
About ten years after taking delivery of the last of a dozen high-wheeled passenger Pacifics (Locobase 3310), the RF&P reworked the firebox to gain more heating surface area. Two of the arch tubes were deleted, leaving 16 sq ft (1.5 sq m) and the shops added 75 sq ft (6.95 sq m) of thermic syphons. The locomotives also gained a lot of weight, adding 6 1/2 short tons to the adhesive figure, and almost 12 tons to the engine weight.
The entire class went to the scrappers in 1950 when the RF&P dieselized.
Other than the Wootten-firebox engines of the anthracite lines, this class had one of the largest grates of all North American Pacifics. RME noted the road's 116 miles (187 km) between Washington and Richmond was the route over which all of the through northern connections of the Seaboard and the Atlantic Coast Lines ran. During the winter, "these trains ...are frequently very heavy, and are hauled at an average speed, including from two to six stops, of 36 to 42 miles per hour [58-67.6 km/h]".
Five arch tubes contributed 34 sq ft (3.15 sq m) to the direct heating surface area. Boiler pressure later raised to 225 psi and TE increased to 52,050 lb (23,610 kg). Fitted with mechanical stokers. Piston valves measuring 14" (356 mm) in diameter supplied steam to the cylinders.
Later (1947) operated by the Chesapeake & Ohio as class F-20 and renumbered 486-489. The first two were scrapped in May 1952, the last two in November 1952.
Firebox heating surface area includes 29.2 sq ft (2.7 sq m) in four arch tubes in the firebox heating surface. Baldwin's specs show both the original heating surface estimates and inked corrections; the latter appear in Locobase's specifications.
The July 1916 Railway Mechanical Engineer (RME) article on the design notes that the Richmond, Fredericksburg & Potomac service on which these engines operated ran at an average of 36-42 mph (58-68 km/h) with six stops pulling very heavy trains.
RME notes the class's 14" (356 mm) "Jack Wilson" balanced slide valves. The first two used Baker valve gear while the last four adopted Southern gear.
When this class was later updated, the firebox heating surface increased to 316.2 sq ft (29.4 sq m), to which arch tubes contributed 15.2 sq ft (1.4 sq m) and thermic syphons 70 sq ft (6.5 sq m).
Passenger Pacifics later rebuilt with cast trailing trucks and Elesco feedwater heaters. Ran until 1950.
Light Pacific built with superheaters. These were delivered to the RF & P's subsidiary Washington Southern at the same time as the Alco-Richmond engines (Locobase 163) but were lighter. Their 14" (356 mm) piston valves supplied steam to the cylinders.
Later, the RF&P revised the power dimensions, reducing cylinder volume by decreasing cylinder diameter to 23 inches (584 mm) and driver diameter by four inches to 69" (1,753 mm) while increasing boiler pressure to 200 psi (13.8 bar). They also added 31 sq ft (2.9 sq m) in arch tubes, bringing the direct heating surface total to 225 sq ft (20.9 sq m) and total evaporative heating surface to 3,125 sq ft (290.3 sq m).
The first four were scrapped before US entry into World War Two. Somehow, the 55 remained on the roster until April 1950.
Built for the Washington Southern at about the same time only a few years after Baldwin built Pacifics for the RF & P (Locobase 5694) , these engines differed primarily in the type of valve gear. They were later superheated along the same lines as the 201 class.
These were the first Pacifics on the RF & P; 10 were built by Baldwin for the Washington Southern in 1904, while the other 5, appropriately enough, were supplied to the RF & P by Alco's Richmond works a year later. Virtually identical to the Harriman Light Pacific design then being delivered to the Southern Pacific (Locobase 4407) and Union Pacific (Locobase 4408), the design was relatively small even at that early date.
A few of the class were later superheated; see Locobase 7114.
These were delivered with slide valves enjoying a 6" travel. One notable ratio is the relatively small firebox heating surface. As these Pacifics operated for several decades (retirements in a wide span from 1937 to 1950), it's not surprising that they were later superheated. See Locobase 7112.
|Specifications by Steve Llanso|
|Class||151 - superheated||201 - superheated||264||301||301||325||401||51 /251||56 / 256||60 / 151||80 / 201|
|Railroad||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Washington Southern (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)||Richmond, Fredericksburg & Potomac (RF&P)|
|Road Numbers||151, 153, 156||80-85 / 201-206||90-94 / 264-268||301-312||10-21 / 301-312||325-328||1-6 / 401-406||51-55 / 251-255||256-263||60-74 / 151-165||80-85|
|Builder||shops||RF&P||Alco-Richmond||RF&P||several||Baldwin||Baldwin||Baldwin||Richmond||several||Burnham, Williams & Co|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.37||0.39||0.37||0.37||0.37||0.36||0.38||0.39||0.37||0.39||0.39|
|Overall Wheelbase (engine & tender)||65.56'||64.56'||67.50'||73.87'||73.75'||74.33'||72.33'||68.67'||64.31'||58.45'||61.96'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||142500 lbs||156000 lbs||161500 lbs||194000 lbs||207000 lbs||208000 lbs||188000 lbs||151200 lbs||156730 lbs||116620 lbs||143750 lbs|
|Engine Weight||210000 lbs||249420 lbs||244000 lbs||287000 lbs||310600 lbs||342600 lbs||293000 lbs||240000 lbs||235000 lbs||180560 lbs||230800 lbs|
|Tender Light Weight||155500 lbs||137900 lbs||154200 lbs||190000 lbs||217600 lbs||210200 lbs||179000 lbs||130000 lbs||138200 lbs||130000 lbs||350000 lbs|
|Total Engine and Tender Weight||365500 lbs||387320 lbs||398200 lbs||477000 lbs||528200 lbs||552800 lbs||472000 lbs||370000 lbs||373200 lbs||310560 lbs||580800 lbs|
|Tender Water Capacity||7000 gals||7000 gals||8000 gals||10000 gals||11000 gals||10000 gals||10000 gals||8000 gals||8000 gals||6500 gals||7000 gals|
|Tender Fuel Capacity (oil/coal)||12 tons||12 tons||16 tons||16 tons||16 tons||16 tons||15 tons||16 tons||12 tons||15 tons||15 tons|
|Minimum weight of rail (calculated) on which locomotive could run||79 lb/yard||87 lb/yard||90 lb/yard||108 lb/yard||115 lb/yard||116 lb/yard||104 lb/yard||84 lb/yard||87 lb/yard||65 lb/yard||80 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||200 psi||200 psi||200 psi||200 psi||200 psi||210 psi||200 psi||185 psi||200 psi||200 psi||200 psi|
|Cylinders (dia x stroke)||21" x 26"||23" x 28"||23" x 28"||26" x 28"||26" x 28"||27" x 28"||26" x 28"||24" x 28"||22" x 28"||20" x 26"||22" x 28"|
|Tractive Effort||28250 lbs||34494 lbs||34494 lbs||42903 lbs||42903 lbs||48581 lbs||47320 lbs||34741 lbs||31559 lbs||26000 lbs||31559 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||5.04||4.52||4.68||4.52||4.82||4.28||3.97||4.35||4.97||4.49||4.55|
|Firebox Area||226 sq. ft||215 sq. ft||273 sq. ft||263 sq. ft||325 sq. ft||278 sq. ft||248.60 sq. ft||196 sq. ft||180 sq. ft||176.70 sq. ft||190 sq. ft|
|Grate Area||49.50 sq. ft||49.50 sq. ft||49.50 sq. ft||66.70 sq. ft||66.70 sq. ft||75.80 sq. ft||67 sq. ft||49.50 sq. ft||49.50 sq. ft||49.50 sq. ft||49.50 sq. ft|
|Evaporative Heating Surface||2199 sq. ft||3223 sq. ft||3159 sq. ft||4205 sq. ft||4267 sq. ft||4175 sq. ft||4162 sq. ft||3084 sq. ft||4097 sq. ft||2967 sq. ft||4107 sq. ft|
|Superheating Surface||553 sq. ft||812 sq. ft||709 sq. ft||975 sq. ft||975 sq. ft||1078 sq. ft||979 sq. ft||709 sq. ft|
|Combined Heating Surface||2752 sq. ft||4035 sq. ft||3868 sq. ft||5180 sq. ft||5242 sq. ft||5253 sq. ft||5141 sq. ft||3793 sq. ft||4097 sq. ft||2967 sq. ft||4107 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||210.98||239.37||234.62||244.39||247.99||225.01||241.89||210.36||332.57||313.84||333.38|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9900||9900||9900||13340||13340||15918||13400||9158||9900||9900||9900|
|Same as above plus superheater percentage||11880||11880||11682||15875||15875||19261||15946||10897||9900||9900||9900|
|Same as above but substitute firebox area for grate area||54240||51600||64428||62594||77350||70640||59167||43149||36000||35340||38000|