Central RR of New Jersey 4-4-2 "Atlantic" Type Locomotives

Class P-1a (Locobase 10764)

Data from Angus Sinclair, Twentieth Century Locomotives (New York: Railway and Locomotive Engineering, 1904), pp.580-582 . Works numbers were 20965-20966, 20983.

This set of camelback Atlantics was smaller and lighter than the Brooks sextet that had appeared a year earlier (Locobase 5331). In 1909-1910 the three were rebuilt with 79" drivers, but as they lacked the sheer size and grate of the P-6s, they were not superheated.

574 was scrapped first in June 1928, with 572 following a month later, and 573 finishing the class in June 1930.

Class P-6 (Locobase 5331)

Data from table in AERJ July 1903. Like all the other Atlantics on the CNJ, these were camelbacks with very tall drivers. Apparently successful, they endured until 1946-1947.

Builder info from B.Rumary, 25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND and Jeremy Lambert as supplied by Allen Stanley in March 2004. Works #3951-3953 in August 1901 and numbered 588-590, renumbered 591-593 soon thereafter. Cannot tell about the other two.

http://www.insighting.co.uk/homauchchunk/steam_class.htm for photos and further comments.

Class P-6 superheated (Locobase 9447)

Data from CNJ 7 - 1944 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Locobase 5331 shows the sextet of Atlantics as they entered service in 1901. Unlike many of the other American railroads that operated 4-4-2s or Camelbacks, the CNJ held onto their doubly unusual P-6s until the end of steam. But the engines were quite different after a substantial makeover that included increasing piston diameter by 1 1/2" in cylinders supplied by 12" piston valves and reducing the driver diameter by 6 inches. At the same time, adhesion weight went up by more than 15 tons to handle the higher tractive effort. A reconfigured boiler substituted 24 flues (and their superheater elements) for 155 small tubes. Finally, the tender held more water and coal and weighed almost 15 tons more than its older counterpart.

Specifications
Class	P-1a	P-6	P-6 superheated
Locobase ID	10764	5331	9447
Railroad	Central RR of New Jersey	Central RR of New Jersey	Central RR of New Jersey
Whyte	4-4-2	4-4-2	4-4-2
Road Numbers	597-599 / 573-574	590-595	590-595
Gauge	Std	Std	Std
Builder	Burnham, Williams & Co	Brooks	CNJ
Year	1902	1901	1917
Valve Gear	Stephenson	Stephenson	Walschaert
	Locomotive Length and Weight
Driver Wheelbase	7.25'	7.67'	7.67'
Engine Wheelbase	26.42'	29.83'	29.92'
Ratio of driving wheelbase to overall engine wheebase	0.27	0.26	0.26
Overall Wheelbase (engine & tender)	53.17'	53.67'	58.54'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	84100 lbs	99400 lbs	127800 lbs
Engine Weight	151000 lbs	191000 lbs	215700 lbs
Tender Light Weight	99000 lbs	124000 lbs	153800 lbs
Total Engine and Tender Weight	250000 lbs	315000 lbs	369500 lbs
Tender Water Capacity	5000 gals		7500 gals
Tender Fuel Capacity (oil/coal)			13 tons
Minimum weight per yard of rail on which locomotive could run	70 lb rail	83 lb rail	107 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	84.50"	85"	79"
Boiler Pressure	200 psi	210 psi	210 psi
Cylinders (dia x stroke)	18" x 26"	20.5" x 26"	22" x 26"
Tractive Effort	16948 lbs	22946 lbs	28433 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.96	4.33	4.49
	Heating Ability
Firebox Area	170.70 sq. ft	174 sq. ft	173.90 sq. ft
Grate Area	73 sq. ft	82 sq. ft	81.63 sq. ft
Evaporative Heating Surface	2174	2967	2188
Superheating Surface			460
Combined Heating Surface	2174	2967	2648
Evaporative Heating Surface/Cylinder Volume	283.90	298.72	191.27
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	14600	17220	17142
Same as above plus superheater percentage	14600	17220	20571
Same as above but substitute firebox area for grate area	34140	36540	43823
Power L1	11136	11493	17397
Power MT	583.84	509.81	600.22