New York Central / Big Four 4-8-2 "Mountain" Type Locomotives


The New York Central Railroad needed a successor for its 4-6-2 "Pacific" that it was using for fast freight and selected the 4-8-2 wheel arrangement for a trail. In 1916, it bought a single "Mountain" type locomotive (road number 2500) from the American Locomotive Company and put it to the test. Satisfied with its performance, the NYC decided that the name "Mountain" would not be appropriate for a river level railroad and chose to call the 4-8-2 wheel arrangement "Mohawk" on its railroad. Twenty-nine more "Mohawks" were delivered by the end of the year. These thirty, ALCO built, locomotives (road numbers 2500 through 2529) were designated Class L-1a and had 28 x 28 cylinders, 69" drivers, a 200 psi boiler pressure and exerted 54,084 lbs of tractive effort.

During 1917 and 1918, 55 "Mohawks" designated Class L-1b (road numbers 2530 through 2584) came from ALCO and in 1918, one hundred 4-8-2s would arrive from the Lima Locomotive Works. These Lima built locomotives, Class L-1c (road numbers 2585 through 2639) and Class L-1d (road numbers 2640 through 2684) were duplicates of the ALCO built Class L-1a locomotives.

Between 1925 and 1930, the NYC bought a total of three hundred more "Mohawks" and designated them Class L-2. All 300 of the L-2 Mohawks were eventually numbered 2700 through 2999. Those L-2 Mohawks originally numbered 2450 through 2499 were renumbered 2950 through 2999 in 1936.

In the 1940s, 115 more "Mohawks" were added to the roster making a total of 600 4-8-2s built for the New York Central. This last group included the 65 Class L-3 (road numbers 3000 through 3034 and 3050 through 3064 from ALCO and road numbers 3035 through 3049 from Lima) and the 50 Class L-4 (road numbers 3100 through 3149 from Lima).

The NYC performed heavy repairs on and did rebuilding of locomotives at shop complexes such as those at Beech Grove, IN and Collinwood, OH.

The L-3 and L-4 Mohawks were built without smoke deflectors, and were the only Mohawks retrofitted with them. The L-3a Mohawks were built with roller bearings on all axles, but the L-3b and L-3c Mohawks were built with roller bearings on all axles except those of the driving wheels. The L-4 Mohawks were built with roller bearings on all axles.

The L-3 Mohawks were built with Boxpok driving wheels and the L-4 Mohawks were built with either Boxpok or Scullin Disc driving wheels. These wheels had a nickel content of 2-3 percent, but no NYC engine was equipped with stainless steel drivers. According to Mr. Gerbracht, stainless steel has metallurgical properties which make it unsuitable for use in driving wheel centers or tires.

There are two surviving NYC "Mohawks": number 2933 at the Museum of Transportation in St. Louis, MO and number 3001 at the National NYC Railroad Museum in Elkhart, IN.

Class Details by Steve Llanso

Class L-1a (Locobase 4793)

Data from "NYC 4-8-4 Type Freight Locomotives", Railway Mechanical Engineer (Vol 92, No 2) , pp. 77-80.

The first of a numerous stud of Mountains (known as Mohawks on the NYC). Schenectady built the first two batches 2500-2584) and Lima finished off the class in 1918.

These were not the engines that made the 4-8-2 such a staple on the Water Level Route. For one thing, they were completed without automatic stokers. This meant, according to the New York Central Museum website (, that they couldn't use all the potential in their boilers. Moreover, they were hard on the track.

Although the proportions of boiler to cylinder and to grate were approximately the same and L-1s had the same 14" (356 mm) piston valves, later Mohawks had bigger grates and boilers as well as a longer stroke and higher boiler pressure. By the mid-1930s, 50 of the 185 L-1s had been scrapped.

Class L-2a/L-2c (Locobase 444)

Boiler had Elesco feedwater heater, valve motion limited cutoff. NY, O & W 459-460 similar. Like the L-1s, these Mohawks were limited to a 60-mph maximum speed. But their bigger boiler and grate set the standard for later NYC 4-8-2s.

Data from the 1930 guide to Dimensions and Classifications of Locomotives seen on (May 2003) and the 1946 guide from the same site. The tube count is from the 1946 version.

Class L-2b, d (Locobase 213)

Boiler had feedwater heater, valve motion

limited cutoff. Slightly larger boilers than the earlier L-2as. More important, their cast-steel engine beds, roller bearings, lightweight main and side rods meant the NYC could raise the maximum speed to 80 mph, thus making them truly dual-purpose locomotives. According to, L-3s developed 4,100 hp at 57 mph, which was a 23 1/2% increase over the L-2ds.

Known as Mohawks in NYC service, 50 of this class went to the Big Four (CCC&StL).

Class L-3a (Locobase 214)

The first 25 of these dual-service engines were assigned to passenger trains and fitted with roller bearings for lower resistance and faster running. Pressing the boiler at 250 psi meant smaller cylinders to fill and still greater power. Drury (1993) claims they were the equal of the better-known Hudsons at passenger running while the 4-6-4s couldn't haul freight. The L-4s that followed the L-3 class (Locobase 215) had drivers that were 3" taller.

The website puts it more strongly about both the L-3s and L-4: "[Their] performance was almost beyond belief. It was nothing for them to bring in a heavy freight drag, be serviced, and leave a few hours later at the head of one of the "Great Steel Fleet' passenger trains." .

Class L-4b (Locobase 215)

Data from tables in 1947 Locomotive Cyclopedia and NYC 1 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Works numbers were 7978-7988 in December 1942, 7989-7994 in January 1943, 7995-7999 in February, 8000-8002 in March, 8292-8298 in October, 8299-8307 in November, 8308-8316 in December.

Firebox heating surface included 35 sq ft of arch tubes as well as a sizable combustion chamber. They were identical to the L-3s (Locobase 214) but had 3"-taller drivers and slightly larger cylinders to compensate. Piston valves measured 14" (356 mm) in diameter and the boiler accommodated a Worthington feed water heater.

Farrington (1976), who didn't particularly like the J-class Hudsons, says these L-4s could climb Albany Hill with seven cars in tow without a helper.

The website puts it more strongly about both the L-3s and L-4: "[Their] performance was almost beyond belief. It was nothing for them to bring in a heavy freight drag, be serviced, and leave a few hours later at the head of one of the "Great Steel Fleet' passenger trains." 50 L-4s ran up about 5.5 million miles (8.55 million km) in their first four years--an average of 27,500 miles (44,275 km) per locomotive per year. 4.5 million (7.25 million km) of that distance was covered hauling passenger trains."

Specifications by Steve Llanso
Class L-1a L-2a/L-2c L-2b, d L-3a L-4b
Locobase ID 4793 444 213 214 215
Railroad New York Central (NYC) New York Central (NYC) Big Four (NYC) New York Central (NYC) New York Central (NYC)
Whyte 4-8-2 4-8-2 4-8-2 4-8-2 4-8-2
Road Numbers 2500-2684 2700-2899 2900-2999 3000-3064 3100-3149
Gauge Std Std Std Std Std
Builder several Alco Alco Alco Lima
Year 1916 1925 1929 1940 1942
Valve Gear Baker Baker Baker Baker Baker
Locomotive Length and Weight
Driver Wheelbase 18' 18' 18' 19' 19'
Engine Wheelbase 39.33' 42' 42.08' 43.08' 43.08'
Ratio of driving wheelbase to overall engine wheebase 0.46 0.43 0.43 0.44 0.44
Overall Wheelbase (engine & tender) 82.54' 84.58' 84.67' 95.96' 95.96'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers 234000 lbs 242000 lbs 247500 lbs 264440 lbs 266500 lbs
Engine Weight 343000 lbs 362500 lbs 368500 lbs 398000 lbs 401100 lbs
Tender Light Weight 166500 lbs 283700 lbs 312700 lbs 379700 lbs
Total Engine and Tender Weight 509500 lbs 646200 lbs 681200 lbs 780800 lbs
Tender Water Capacity 15000 gals 15000 gals 15000 gals 15500 gals 15200 gals
Tender Fuel Capacity (oil/coal) 18 tons 21 tons 28 tons 43 tons 42 tons
Minimum weight of rail (calculated) on which locomotive could run 98 lb/yard 101 lb/yard 103 lb/yard 110 lb/yard 111 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter 69" 69" 69" 69" 72"
Boiler Pressure 190 psi 225 psi 225 psi 250 psi 250 psi
Cylinders (dia x stroke) 28" x 28" 27" x 30" 27" x 30" 25.5" x 30" 26" x 30"
Tractive Effort 51380 lbs 60618 lbs 60618 lbs 60077 lbs 59854 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.55 3.99 4.08 4.40 4.45
Heating Ability
Firebox Area 320 sq. ft 354 sq. ft 345 sq. ft 373 sq. ft 373 sq. ft
Grate Area 66.80 sq. ft 75.35 sq. ft 75.30 sq. ft 75.30 sq. ft 75.30 sq. ft
Evaporative Heating Surface 4430 sq. ft 4646 sq. ft 4556 sq. ft 4676 sq. ft 4676 sq. ft
Superheating Surface 1212 sq. ft 1938 sq. ft 1931 sq. ft 2082 sq. ft 2082 sq. ft
Combined Heating Surface 5642 sq. ft 6584 sq. ft 6487 sq. ft 6758 sq. ft 6758 sq. ft
Evaporative Heating Surface/Cylinder Volume 222.00 233.70 229.17 263.69 253.65
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation 12692 16954 16943 18825 18825
Same as above plus superheater percentage 15357 21870 22025 24661 24661
Same as above but substitute firebox area for grate area 73568 102749 100913 122158 122158
Power L1 18547 31052 30794 40985 41137
Power MT 698.96 1131.53 1097.20 1366.76 1361.22



  • The New York Central System
  • New York Central Historical Society
  • NYC Forum
  • Historic New York Central Steam Photos (Photos courtesy Yesteryear Depot)
  • Memories of New York Central Steam by Arnold Hass (D. Carelton Railbooks)
  • New York Central's Later Power 1910-1968 by Alvin F. Staufer and Edward L. May (Alvin F. Staufer)
  • Rails Along the Hudson by Thomas M. Crawford and Frederick A. Kramer (Quadrant Press)
  • Steam Power of the New York Central System: Vol 1, Modern Power 1915-1955 by Alvin F. Staufer (Alvin F. Staufer)
  • Thoroughbreds by Alvin F Staufer (Alvin F. Staufer)
  • Steam Locomotives of the New York Central Lines, Volume 1, Parts 1 & 2 NYC&HRRR and B&A by William D. Edson and H. L. Vail, Jr., Published by New York Central System Historical Society, Inc.


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

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