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

Class Details by Steve Llanso

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 95 sq ft of syphons and feedwater heaters. Maximum water evaporation rate was calculated at 56,555 lb/hour of which 22,825 lb/hour (40.4%) came from direct heating surfaces. As calculated by the New Haven, maximum steam consumption of 54,580 lb/hour yielded a 104% boiler factor.

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 and a valve motion with 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 by Steve Llanso
Locobase ID8122 216 217
RailroadNew Haven (NYNH&H)New Haven (NYNH&H)New Haven (NYNH&H)
Road Numbers3300-33483501-35073550-3562
Valve GearBakerSouthernWalschaert
Locomotive Length and Weight
Driver Wheelbase18.25'18.25'19.75'
Engine Wheelbase40'40.83'42.25'
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)58200 lbs65300 lbs
Weight on Drivers230500 lbs246000 lbs261000 lbs
Engine Weight334000 lbs362500 lbs379000 lbs
Tender Light Weight184800 lbs288500 lbs
Total Engine and Tender Weight518800 lbs667500 lbs
Tender Water Capacity16000 gals16000 gals16000 gals
Tender Fuel Capacity (oil/coal)10 tons18 tons18 tons
Minimum weight of rail (calculated) on which locomotive could run96 lb/yard103 lb/yard109 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter69"69"69"
Boiler Pressure200 psi265 psi265 psi
Cylinders (dia x stroke)27" x 30"27" x 30"22" x 30" (3)
Tractive Effort53883 lbs71394 lbs71101 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.28 3.45 3.67
Heating Ability
Firebox Area415 sq. ft458 sq. ft451 sq. ft
Grate Area70.30 sq. ft70.80 sq. ft70.80 sq. ft
Evaporative Heating Surface4188 sq. ft4135 sq. ft4085 sq. ft
Superheating Surface1009 sq. ft1758 sq. ft1745 sq. ft
Combined Heating Surface5197 sq. ft5893 sq. ft5830 sq. ft
Evaporative Heating Surface/Cylinder Volume210.66207.99206.33
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation140601876218762
Same as above plus superheater percentage167312439124391
Same as above but substitute firebox area for grate area98770157781155370
Power L1177523410333933
Power MT679.161222.511146.50



Introduction and roster provided by Richard Duley. Class details and specifications provided by Steve Llanso of Sweat House Media.