Norfolk & Western 2-6-6-2 Type Locomotives

Class Z1 (Locobase 1467)

Data from N&W 3-1955 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive collection.

Built by Richmond and Baldwin from 1912-1918 and served until the 1950s on helper-engine duties. EL King, writing in Drury (1993), says that 74 Z1a were refurbished with piston valves for the LP cylinders and Worthington feedwater heaters. These Z1b put about 9 more long tons on the drivers.

Entered service with a boiler pressed to 200 psi; later raised to 225 psi as shown. Firebox heating surface initially included 134 sq ft of arch tubes and syphons in a total of 248 sq ft. A later version shown in the specifications had 22 sq ft of arch tubes as well as area from a combustion chamber.

One was rebuilt as a simple-expansion engine; see Locobase 7824.

Class Z2 (Locobase 7824)

Data from N&W 3-1955 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive collection.

EL King, writing in Drury (1993), says that the N & W rebuilt one of its Z1 compound articulateds (Locobase 1467) as a simple-expansion locomotive, but it was not a success. The boiler was simply too small to supply 4 high-pressure cylinders with steam. Therefore, 1399 remained an only engine until its retirement 6 years later.

Specifications
Class	Z1	Z2
Locobase ID	1467	7824
Railroad	Norfolk & Western	Norfolk & Western
Whyte	2-6-6-2	2-6-6-2
Road Numbers	1315-1489	1339
Gauge	Std	Std
Builder	several	Norfolk & Western
Year	1912	1928
Valve Gear	Baker	Baker
	Locomotive Length and Weight
Driver Wheelbase	10'	10'
Engine Wheelbase	48.83'	48.83'
Ratio of driving wheelbase to overall engine wheebase	0.20	0.20
Overall Wheelbase (engine & tender)	94.56'	94.56'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	376581 lbs	377825 lbs
Engine Weight	440000 lbs	441000 lbs
Tender Light Weight	312700 lbs	286530 lbs
Total Engine and Tender Weight	752700 lbs	727530 lbs
Tender Water Capacity	18000 gals	16000 gals
Tender Fuel Capacity (oil/coal)	26 tons	23 tons
Minimum weight per yard of rail on which locomotive could run	104.61 lb rail	104.95 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	57"	56.50"
Boiler Pressure	225 psi	225 psi
Cylinders (dia x stroke)	22" x 32"	22" x 32" (4)
Low Pressure Cylinders (dia x stroke)	35" x 32"	" x "
Tractive Effort	74498 lbs	104852 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	5.05	3.60
	Heating Ability
Firebox Area	391 sq. ft	391 sq. ft
Grate Area	72.20 sq. ft	72.20 sq. ft
Evaporative Heating Surface	4629	4629
Superheating Surface	971	971
Combined Heating Surface	5600	5600
Evaporative Heating Surface/Cylinder Volume	328.79	164.39
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	16245	16245
Same as above plus superheater percentage	19061.77	19061.77
Same as above but substitute firebox area for grate area	103229.24	103229.24
Power L1	9191.53	11529.81
Power MT	322.86	403.66