Big Four / New York Central 4-8-2 "Mountain" Locomotives in the USA

Class L-1 - later boiler (Locobase 15999)

Data from NYC 1930 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.)

Within a couple of years of the time that 2568 was fitted with a new boiler at the same time it received a third cylinder (Locobase 16001), two of the L-1as described in Locobase 4793 emerged with a variant of that vessel.; 2605 was converted in February 1923, 2518 in April 1925.

The combustion chamber had indeed been replaced by longer boiler tubes, but the basic Type A superheater layout remained the same.

Class L-1a, b, c, d (Locobase 4793)

Data from "New York Central 4-8-2 Type Locomotives," Railway Age Gazette, Volume 63, No 24 (28 December 1917), pp. 1167-1170 . (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones. His 13 March 2016 email linked the L-1 to the earlier K-11 Pacific. Thanks also to Chris Hohl for his 28 March 2019 email noting the increases in engine weights and tender capacities and weights.) Works numbers were 56000, 56027-56055 in 1916, 56910-56964 in 1917-1918 and Lima works numbers were 5499-5553, 5585-5629 in 1918.

The first of a numerous stud of Mountains (known as Mohawks on the NYC). Schenectady built the first two batches 2501-2584), the first thirty designated L-1a, the other 53 L-1b. Lima continued with 2585-2639 (L-1c) and finished off the class with 45 (2640-2684) L-1d in 1918. According to Jason Cippola, the L-1's design was "basically an elongated version of the successful K-11 [Pacific]. The designers stuck with what they knew worked." (See the K-11 entries at Locobase 5578, 13884-13885.) He notes the squared dimensions of the K-11--26" x 26"--and notes the 28" x 28" of the Mohawks.

The RAG report said the engines handled fast freights of 2,500-3,500 tons (75-93 loaded cars) over a 139 mile (224 km) route in five to eight hours of total time. But 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 (nycmuseum.railfan.net/MOHAWK.htm), 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.

Still, this class was big enough to merit upgrades of their own and by 1930, all had been retrofitted with Duplex stokers, almost all had trailing truck boosters, and 117 had feed water heaters. Elescos were installed on 20 L-1a, 18 L-1b, 24 L-1c, and 20 L-1d. Coffins were fitted to 1 L-1a, 14 L-1b, 7 L-1c, and 8 L-1d. 2533, 2610-2612, 2668 received Worthingtons. 2533 was equipped with thermic syphons.

Original adhesion weight was 234,000 lb (110,223 kg) and engine weight 343,000 lb (157,850 kg). In his email, Chris Hohl noted weight increased, especially in those with feed water heaters and boosters. Tender water capacity almost doubled from the original 8,000 US gallons (30,280 litres) and it carried an additional 4 tons (3.6 metric tons) of coal. The original 72,000 lb (32,659 kg) empty and 166,700 lb (75,296 kg) loaded mushroomed to the figures in the specs.

Two L-1b--2568-2569--were converted to a three-cylinder design (25" x 28") in 1922 and 1924, respectively; see Locobases 16000 and 16001.

By the mid-1930s, 50 of the 185 L-1s (almost all those that had not been upgraded with feed water heaters) had been scrapped. By the end of World War Two, most surviving L-1s trailed tenders carrying 22-23 tons of coal.

Class L-1b - 3 cylinder (Locobase 16000)

Data from NYC 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones. and to Chris Hohl for his 25 July 2023 email correcting the valve gear, and supplying original tender weight and caol capacity. )

Locobase 4793 shows the original 1916-1918 L-1a design. 2569 was one of two converted by Alco to three-cylinder operation as part of that company's push to generate more power with lower forces in a given locomotive setup. Each of the three cylinders used an 11" (279 mm) piston valve to supply steam to its cylinder. The 2569 gave up the combustion chamber fitted in the original L-1s. Its tender originally held 16 tons of coal and weighed 267,800 lb (121,472 kg), but coal capacity quickly increased to the 18 tons shown in the specs.

2568, detailed in Locobase 16001, also had the new boiler that would be installed in all the L-1s.

2569 was retired on 1 January 1936 and was broken up in July 1936.

Class L-1b - 3 cylinder,, new boiler (Locobase 16001)

Data from "New York Central Three-Cylinder Locomotive", Railway Mechanical Engineer, Volume 97, No. 11 (November 1925), pp 743-744; and NYC 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Jason Cippola, whose 21 March 2015 email comments triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones. Thanks to Chris Hohl for his 25 July 2023 email correcting the valve gear, engine wheelbase. and original tender weight.)

One of two L-1a converted to a three-cylinder power layout as part of Alco's promotion of that center-cylinder solution to the need for more power. Each of the three cylinders had an 11" (279 mm) piston valve. Its new boiler excluded the combustion chamber of the original design, which, as noted in Locobase 15999, resulted in some of the longest tubes ever installed in a locomotive boiler. Unlike the other L-1 updates, however, the 2568's boiler had only 3 1/2" tubes that held more superheater elements

2568 was retired on 1 January 1936 and were broken up in April 1936.

Class L-2a (Locobase 444)

Data from the 1930 guide to Dimensions and Classifications of Locomotives seen on [] (May 2003). (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.) Works numbers for the L-2a were 66281 in March 1925, 66578-66647 in March 1926, 66648-66676 in May.

Boiler had Elesco feedwater heater, valve motion with limited cutoff of 14" (356 mm) piston valves. Like the L-1s, these Mohawks were limited to a 60-mph (97 kph) maximum speed and they too had only flues with no smaller diameter tubes. But their bigger boiler and grate set the standard for later NYC 4-8-2s. The L-2c (Locobase 15994) were similar, but fitted with Coffin feed water heaters.

NYO&W 459-460 similar.

Class L-2b (Locobase 213)

Data from tables in 1930 Locomotive Cyclopedia. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.) Works numbers were 67742-67757 in February 1929, 67758-67766 in March, 68118-68142 in October.

Known as Mohawks in New York Central service (Locobase 15900), these Mountains followed the NYC's L-2a and duplicated their dimensions.

Boiler had Elesco feed water heaters in 2900-2914 and Worthingtons in 2915-2924, valve motion with limited cutoff operating 14" (356 mm) piston valves.

Slightly larger boilers than the earlier L-2as.

Class L-2c (Locobase 15994)

Data from the 1930 guide to Dimensions and Classifications of Locomotives seen on [] (May 2003). (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.) Works numbers were 67821-67835 in April 1929, 67850 in May, 67851-67875 in April, 67876-67899 in June, 67900-67905 in July, 67906-67914 in August, 67915-67920 in September

The L-2c's Coffin feed water heaters required more room ahead of the drivers compared to the earlier L-2a (Locobase 444). So Schenectady moved the truck 6" (152 mm) further forward, which closed the distance between the truck's rear axle and the rear face of the cylinder. The front truck's axle moved 4" (102 mm) further ahead of the cylinder's front face. They also had valve motion with limited cutoff of 14" (356 mm) piston valves

The Coffin would be replaced and the boiler reconfigured; see Locobase .

Class L-2d (Locobase 15900)

Data from tables in 1930 Locomotive Cyclopedia. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.) Works numbers were 68118-68142 in October 1929, 68093-68103 in February 1930, 68104-68117 in March.

Boiler had Elesco feed water heaters and BK stokers, valve motion with limited cutoff of 14" (356 mm) piston valves.

Slightly larger boilers than the earlier L-2as (Locobase 444). More important, tenders trailing the last 50 engines used water scoops to extend their water range. The class's 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 nycmuseum.railfan.net/MOHAWK.htm, L-3s developed 4,100 hp at 57 mph, which was a 23 1/2% increase over the L-2as.

Known as Mohawks in NYC service, 50 of this class went to the Big Four (CCC&StL); see Locobase 213.

Class L-2d - high-speed conversion (Locobase 16002)

Data from NYC 1 - 1944 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection; P W Kiefer "Research and Design of Steam Passenger Locomotives - Part II", Railway Mechanical Engineer (September 1941), pp. 342-343; and T R Gerbracht, "The Late Mohawks", Central Headlight, Fourth Quarter 2000, pp. 11-32, archived at [], last accessed 4 July 2017. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.)

Boiler had Elesco feed water heaters and BK stokers, valve motion with limited cutoff of 14" (356 mm) piston valves.

These two engines were upgraded after several years as high-speed-service locomotives. Timken roller bearings reduced friction on engine truck and all tender axles. 5998 also received roller bearings on her driving axles. Cylinder diameter dropped by 1 1/2" (38 mm), but boiler pressure increased by 25 psi (1.72 bar). A trailing-truck booster added 13,750 lb (61.16 kN) to starting tractive effort.

In his 1941 review of the trial, Paul Kiefer, chief engineer motive power and rolling stock, reported that since August 1939, the two engines had hauled passenger trains over 200,000 train miles (322,000 km). The main question was whether the heavier L-2s could run at 80 mph (129 kph) without stressing the track. In particular, could a locomotive turning 69" drivers operate at the same maximum speeds as one with 79" drivers. Slow-motion photography showed that at "up to 87 mph [140 kph]...the converted L-2 imposed no greater stress on the track than the J-1 [Hudson]". The level of stress was "well within permissible limits."

These tests led to the development and production of the L-3 class described in Locobase 214.

Class L-3a, b, c (Locobase 214)

Data from tables in 1947 Locomotive Cyclopedia and NYC 1-1944 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange; and Paul W Kiefer "Research and Design of Steam Passenger Locomotives - Part II", Railway Mechanical Engineer (September 1941), pp. 342-343. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones.) Schenectady works numbers were 69337-69361 (L-3a) in 1940 and 69362-69371 in 1940-1941 (L-3b). Lima supplied another 15 in the same years as works numbers 7779-7793. Schenectady finished the class with works numbers 69745-69759 in 1942.

Paul Kiefer ascribed the origin of these dual-service locomotives to the successful tests of the two modified L-2d 4-8-2s described in Locobase 16002. He credited the close cooperation of Alco, Locomotive Superheater Company, and Timken Roller Bearing Company. The original plan was to build a boiler of nickel steel, but carbon steel was used, which required a lower boiler pressure setting. Likewise, the designers rejected adoption of a four-wheel trailing truck to restrict locomotive and tender wheel base to less than 100 ft (30.5 m) while using a tender carrying 43 tons (39.1 metric tons) of coal and a faster-acting water scoop that increased water supply 20%.

The first 25 of these dual-service engines were assigned to passenger trains. All of the L-3s were fitted with roller bearings in both the lead bogie and trailing truck as well as the tender's six axles for lower resistance and faster running; only the driver still used plain bearings. Pressing the boiler at 250 psi meant smaller cylinders to fill and still greater power. Valve motion set with limited cutoff of 14" (356 mm) piston valves.

The L-3b and c were fitted with trailing-truck boosters that added 14,000 lb (6,350 kg) to starting tractive effort. L-3a and L-3c had Worthington feed water heaters. L-3b mixed in Worthingtons (3025-3034) in the Schenectadies and Elescos in the Limas (3035-3049).

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 (Locobase 215) that followed the L-3 class (Locobase 215) had drivers that were 3" taller.

The nycmuseum.railfan.net/MOHAWK.htm 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.".

In the latter service, their huge twelve-wheel tenders ensured endurance. Although tank capacity seemed almost modest, track pans between the rails on the Water Level Route meant the engine could take on water while scarcely slowing down. 86,000 lb (39,009 kg) of coal cut the number of stops for refuelling considerably.

Class L-4a, 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 Rail Data Exchange. (Thanks to Jason Cippola, whose 21 March 2015 triggered a complete overhaul of the New York Central's Mohawk entries and the creation of several new ones. Thanks also to Dr Torsten Sohns for his 8 April 2020 email noting the L-4a designation for 3100-3124.) Works numbers were L-4a: 7978-7988 in December 1942, 7989-7994 in January 1943, 7995-7999 in February, 8000-8002 in March; L-4b: 8292-8298 in October, 8299-8307 in November, 8308-8316 in December.

Firebox heating surface included 35 sq ft (3.25 sq m) of arch tubes as well as a sizable combustion chamber. They were identical to the L-3s (Locobase 214) but had 3" (76.2 mm) 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. They took a further step in friction reduction by having the driving axles also turn in roller bearings

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 Central's extensive track pan network meant an L-4 could trail a tender carrying enough coal to make it halfway from New York to Chicago and enough water to make it to the next track pan. An enormous vessel, the six-axle tender measured 48 ft 2 in (14.68 m) long. The L-4b's tender carried slightly less coal and water (42 tons/38.2 metric tons and 15,200 gallons/57,532 litres).

The nycmuseum.railfan.net/MOHAWK.htm website puts the positive case 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.

The entire class was retired in 1954-1957.