New Haven 4-8-2 "Mountain" Type Locomotives

Class R-1-b (Locobase 8122)

Data from NH 1962 St Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The United States Railroad Administration's Mountain design proved an excellent fit for the New Haven's fast freight requirements, so in addition to the 10 supplied during the USRA's administration, the railroad bought 39 more - 30 in 1920, 9 in 1924. Over time, the class (R-1, R-1-a, R-1-b) was updated with syphons and feedwater heaters. To stave off the need to replace the class, the New Haven replaced the class's Southern valve gear with Baker gear in 1940 and fitted them with mechanical lubricators.

Thus equipped, all served the New Haven throughout World War II. Retirements occurred from the end of the war to the end of steam (1946-1951).

Class R-2a (Locobase 216)

This was a quirky mixture of new ideas and auxiliary equipment that in many cases was unsatisfactory. Specified by the New Haven's mechanical manager, WL Bean, the McClellon boiler had a water-tube firebox that leaked and let in cold air. Ultimately all New Haven engines originally delivered with the McClellon boiler had a conventional boiler fitted in 1929. Other problems included a balky DuPont-Simplex mechanical stoker (replaced by an HT-2 in the 1930s) and Southern valve gear replaced by Walschaerts or Baker gear. The design also came equipped with feedwater heater, valve motion limited cutoff.

The R-2s ran until 1949-1951.

Class R-3 (Locobase 217)

Boiler had feedwater heater. Unusual 3-cylinder variant of earlier R-2 that also came with the McClellon watertube firebox boiler design. Within a year they'd been reboilered. Note relatively small number of tubes and flues. Although the middle cylinder was a maintenance headache, financial stringency prevented conversion to a two-cylinder layout (as other railroads had done). They ran until 1949-1951.

Specifications
Class	R-1-b	R-2a	R-3
Locobase ID	8122	216	217
Railroad	New Haven	New Haven	New Haven
Whyte	4-8-2	4-8-2	4-8-2
Road Numbers	3300-3348	3501-3507	3550-3562
Gauge	Std	Std	Std
Builder	Alco-Schenectady	Alco	Alco-Schenectady
Year	1918	1926	1927
Valve Gear	Baker	Southern	Walschaert
	Locomotive Length and Weight
Driver Wheelbase	18.25'	18.25'	19.75'
Engine Wheelbase	40'	40.83'	42.25'
Ratio of driving wheelbase to overall engine wheebase	0.46	0.45	0.47
Overall Wheelbase (engine & tender)	75.62'	83.92'	85.33'
Axle Loading (Maximum Weight per Axle)	58100 lbs
Weight on Drivers	230500 lbs	246000 lbs	260000 lbs
Engine Weight	334000 lbs	362500 lbs	379000 lbs
Tender Light Weight	184800 lbs
Total Engine and Tender Weight	518800 lbs	0	0
Tender Water Capacity	16000 gals	16000 gals	16000 gals
Tender Fuel Capacity (oil/coal)	10 tons	18 tons	18 tons
Minimum weight per yard of rail on which locomotive could run	96.04 lb rail	102.50 lb rail	108.33 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	69"	69"	69"
Boiler Pressure	200 psi	265 psi	265 psi
Cylinders (dia x stroke)	27" x 30"	27" x 30"	22" x 30" (3)
Tractive Effort	53883 lbs	71394 lbs	71101 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.28	3.45	3.66
	Heating Ability
Firebox Area	415 sq. ft	458 sq. ft	451 sq. ft
Grate Area	70.30 sq. ft	70.80 sq. ft	70.80 sq. ft
Evaporative Heating Surface	4106	4135	4085
Superheating Surface	1009	1758	1745
Combined Heating Surface	5115	5893	5830
Evaporative Heating Surface/Cylinder Volume	206.54	207.99	206.33
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	14060	18762	18762
Same as above plus superheater percentage	16833.52	24359.08	24377.73
Same as above but substitute firebox area for grate area	99372.83	157577.10	155287.50
Power L1	17656.90	34102.82	33932.81
Power MT	675.52	1222.50	1150.91