PRR D7

PRR D7
PRR D7a #953 in its builders' portrait
Power type	Steam
Builder	PRR Altoona Works[1]
Build date	1882–1891[1]
Total produced	58 D7, 61 D7a[1]
Configuration	4-4-0
UIC classification	2′B
Gauge	4 ft 8 1⁄2 in (1,435 mm)
Leading wheel diameter	30 in (762 mm) (D7)[2] 33 in (838 mm) (D7a)[3]
Driver diameter	68 in (1,727 mm) (D7)[2] 62 in (1,575 mm) (D7a)[3]
Wheelbase	22 ft 7 1⁄2 in (6.90 m)[2][3]
Length	58 ft 0.6 in (17.69 m)[3]
Height	14 ft 4 in (4.37 m)[3]
Axle load	32,650 lb (14.8 tonnes)[3]
Weight on drivers	56,700 lb (25.7 tonnes) (D7) [2] 58,700 lb (26.6 tonnes)[3]
Locomotive weight	93,500 lb (42.4 tonnes) (D7)[2] 96,330 lb (43.7 tonnes) (D7a)[3]
Locomotive & tender combined weight	160,880 lb (73.0 tonnes)[3]
Fuel type	Anthracite coal[1]
Fuel capacity	12,000 lb (5.4 tonnes)[3]
Water capacity	2,400 US gal (9,100 l; 2,000 imp gal)[3]
Boiler pressure	140 lbf/in² (970 kPa)[3]
Firegrate area	34.75 sq ft (3.23 m2)[3]
Heating surface: Tubes	1,134 sq ft (105.35 m2)[3]
Heating surface: Firebox	155 sq ft (14.40 m2)[3]
Heating surface: Total	1,289 sq ft (119.75 m2)[3]
Cylinders	2[3]
Cylinder size	17 × 24 in (432 × 610 mm)[3]
Valve gear	Stephenson
Valve type	Slide valves
Tractive effort	12,138 lbf (53.99 kN) (D7) 13,313 lbf (59.22 kN) (D6a)
Factor of adhesion	4.7 (D7) 4.4 (D7a)

Class D7 (formerly Class A (anthracite), pre-1895) on the Pennsylvania Railroad was a class of 4-4-0 steam locomotive.^[4] Fifty-eight were built by the PRR's Altoona Works between 1882–1891 with 68 in (1.73 m) drivers, while sixty-one of class D7a were constructed with 62 in (1.57 m) drivers.^[1]

The D7 was fundamentally an anthracite-burning version of the PRR D6, with a larger fire-grate in order to burn the slower-burning, harder coal.^[5]

References

1. ^ ^{a b c d e} "PRR Steam Roster". Northeast Rails. http://www.northeast.railfan.net/prr_steam2.html. Retrieved 2007-12-31. 
2. ^ ^{a b c d e} Pennsylvania Railroad. "D7 Diagram". PRR.Railfan.net. http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=d7_olda_anth.gif&sel=ste&sz=sm&fr=. Retrieved 2008-08-17. 
3. ^ ^{a b c d e f g h i j k l m n o p q r} Pennsylvania Railroad. "D7a Diagram". PRR.Railfan.net. http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=d7a.gif&sel=ste&sz=sm&fr=. Retrieved 2008-08-17. 
4. ^ Staufer, Alvin F. and Pennypacker, Bert (1962). Pennsy Power: Steam and Electric Locomotives of the Pennsylvania Railroad, 1900–1957. Staufer. LCCN 62-20878. 
5. ^ Warner, Paul T. (1924). Motive Power Development on the Pennsylvania railroad System. Philadelphia: Baldwin.