4-8-4 "Northern" Steam Locomotive
Under the Whyte notation for the classification of steam locomotives, 4-8-4 represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type was first used by the Northern Pacific Railway and is consequently most commonly known as a Northern.

Development
The 4-8-4 wheel arrangement was an obvious progression from the 4-8-2 Mountain type and, like the 2-8-4 Berkshire and 4-6-4 Hudson types, an example of the "Super Power" concept in steam locomotive design that made use of the larger firebox that could be supported by the four-wheel trailing truck, which allowed improved free steaming, particularly at speed. This was combined with the stability at speed brought about by the four-wheel leading truck and the greater adhesion of the eight driving wheels. The evolution to the 4-8-4 type occurred in the United States of America soon after the Lima Locomotive Works introduced the concept of "Lima Super Power" in 1925. The prototype was built to Super Power principles by American Locomotive Company (ALCO) for the Northern Pacific Railway (NP) in 1926, with a four-wheel trailing truck to carry the weight of a very large firebox that was designed to burn low quality lignite coal. The potential benefit of supporting a firebox with a 100 square feet (9.3 square meters) grate on a four-wheel trailing truck was quickly realized by locomotive designers since, given the truck’s additional weight of approximately 15,000 pounds (6,804 kilograms) and the 55,000 pounds (24,948 kilograms) of additional engine weight that a four-wheel truck could carry above that of a two-wheel truck, the difference of 40,000 pounds (18,144 kilograms) was available to be used for increased boiler capacity.

The 4-8-4 type arrived on the locomotive scene at a time when nearly all the important design improvements had already been proven, such as the superheater, mechanical stoker, outside valve gear, the Delta trailing truck and the one-piece bed frame of cast steel with integrally cast cylinders, which did much to advance the application of roller bearings on steam locomotives since it gave the strength and rigidity to hold them in correct alignment. In 1930, the Timken Company actually used a 4-8-4 built by ALCO with roller bearings on all axles and called the Timken 1111, to demonstrate the value of their sealed roller bearings over nearly every mainline in the United States. The Timken 1111 was subsequently sold to the NP, where it became NP no. 2626, their sole Class A-1 locomotive.

The stability of the 4-8-4 wheel arrangement enabled it to be provided with driving wheels of up to 80 inches (2,032 millimeters) diameter for high speed passenger and fast freight operation and, with the latest lateral control devices, the type was flexible on curves in spite of its eight-coupled drivers. The increased boiler size that became possible with this type, together with the high axle loads permitted on mainlines in North America, resulted in the design of some massive locomotives with all-up weights exceeding 350 tons with tender included. The 4-8-4 proved itself suitable for both express passenger and fast freight service. While it was not suited to heavy drag freight trains, faster and lighter trains were well suited to the type.

Although locomotives of the 4-8-4 wheel arrangement were used in a number of countries, those that were developed outside North America included various design features which set them apart from North American practice. The United States, Canada and Mexico were the domains of the North American 4-8-4, and scaled down examples of the type were exported by two American builders, ALCO and Baldwin Locomotive Works, for 1,000 mm (3 ft 3 3⁄8 in) meter gauge lines in Brazil. Most were two-cylinder locomotives, but four classes of three-cylinder 4-8-4s were built:

The simplex 06 class by the Deutsche Reichsbahn in Germany.
The simplex H class by the Victorian Railways in Australia.
The compound 242A1 class of the Société Nationale des Chemins de fer Français (SNCF) in France.
An experimental high-pressure compound locomotive of the New York Central (NYC).

The Northern name
Since the 4-8-4 was first used by the Northern Pacific Railway, the type was named "Northern". Most North American railroads used this name, but some adopted different names.

"Big Apple" on the Central of Georgia Railway (CG).
"Confederation" on the Canadian National Railway (CN).
"Dixie" on the Nashville, Chattanooga and St. Louis Railway (NC).
"Golden State" on the Southern Pacific Railroad (SP), temporarily renamed "General Service" during the Second World War and also referred to as "GS" by Western Pacific for those GSs which were diverted to the WP from SP's order by the War Production Board.
"Greenbrier" on the Chesapeake and Ohio Railway (C&O).
"Niagara" on the New York Central Railroad (NYC).
"Niágara" on the Ferrocarriles Nacionales de México (N de M) and in Brazil.
"Pocono" on the Delaware, Lackawanna and Western Railroad (Lackawanna).
"Potomac" on the Western Maryland Railway (WM).
"Western" on the Denver and Rio Grande Western Railroad (Rio Grande).
"Wyoming" on the Lehigh Valley Railroad (LV).

The Richmond, Fredericksburg and Potomac Railroad (RFP) gave each of its three 4-8-4 classes a separate name, the "General" of 1937, the "Governor" of 1938 and the "Statesman" of 1944.

Demise
The big-wheeled 4-8-4 was at home on heavy passenger trains and quite capable of speeds over 100 miles per hour (160 kilometres per hour), but freight was the bread and butter of the railroads and in that service the Northern had limitations. The adhesive weight on a 4-8-4 was limited to about 60% of the engine's weight, not including the dead weight of the tender. Henry Bowen, the Chief Mechanical Engineer of the Canadian Pacific Railway (CPR) from 1928 to 1949, recognized this and, after testing the first two CPR K-1a Northerns introduced by his predecessor, he designed a 2-10-4 Selkirk type using the same boiler. The resulting T-1a Selkirk locomotive had the same number of axles as the Northern, but the driving wheels were reduced from 75 to 63 inches (1,905 to 1,600 millimeters) in diameter, while the additional pair of driving wheels increased the tractive effort by 27%. In a later variant, Bowen added a booster to the trailing truck, enabling the big Selkirk to exert nearly 50% more tractive effort than the similar-sized K-1a Northern.

However, when it was demonstrated that a three-unit EMD F3 diesel-electric consist that weighed a little less than the total engine and tender mass of a CPR K-1a Northern could produce nearly three times its tractive effort, even new Super Power steam locomotives were retired as quickly as finance allowed.

United States
The American 4-8-4 was a heavy locomotive, with nearly all examples in the United States having axle loads of more than 30 short tons (27 tonnes). On railroads with rail of 130 to 133 pounds per yard (64 to 66 kilograms per metre), axle loads of more than 36 short tons (33 tonnes) were permitted. Exceptionally heavy Northerns were therefore introduced on the Atchison, Topeka and Santa Fe (Santa Fe), Chicago and North Western (CNW), Chesapeake and Ohio (C&O), Milwaukee Road, Northern Pacific (NP), Norfolk and Western (N&W), Spokane, Portland and Seattle (SP&S) and Western Maryland (WM) railroads. The preserved SP&S no. 700 is a surviving example of the three SP&S Class E-1 locomotives, which had the heaviest axle load of all at 37.1 short tons (33.7 tonnes). The lightest Northerns in the United States were the six H-10 class locomotives of the Toledo, Peoria and Western (TPW), with an axle load of 23 short tons (21 tonnes).

Northerns Used on Long Runs

The Santa Fe Northerns were rostered to haul the Chief and Fast Mail trains between La Junta, Colorado and Los Angeles across 1,255 miles (2,020 kilometers), and also handled the Grand Canyon Limited between Los Angeles and Wellington, Kansas, across 1,534 miles (2,469 kilometers). From 1942, they ran through from Los Angeles to Kansas City via the Belen Cutoff and Amarillo, Texas, a distance of 1,789 miles (2,879 kilometers), setting a new record for through steam locomotive rosters.
The Niagaras of the New York Central Railroad (NYC) also accomplished long runs on New York to Chicago passenger trains, including the Chicagoan and the Commodore Vanderbilt.
Northern Pacific 4-8-4s hauled the North Coast Limited across 1,008 miles (1,622 kilometers) from St. Paul, Minnesota, to Livingston, Montana.

Several of the earlier 4-8-4 locomotive models were modified or rebuilt during their service lives.

Santa Fe developed their Northerns for years. The fourteen 3751 class locomotives that were introduced in 1927 and 1928 were of conservative design, with 73 inches (1,854 millimeters) diameter driving wheels and a boiler pressure of 210 pounds per square inch (1,400 kilopascals). In 1938, these locomotives were rebuilt with more modern features, including new 80 inches (2,032 millimeters) diameter Boxpok driving wheels, increased size steam passages to and from the cylinders, the boiler pressure raised to 230 pounds per square inch (1,600 kilopascals) and roller bearings on all engine axles. This gave them a maximum drawbar power of 3,600 horsepower (2,700 kilowatts) at 50 miles per hour (80 kilometers per hour). Engine no. 3752 was equipped with Franklin rotary cam poppet valve gear and achieved the very low steam rate of 13.5 lb per indicated horsepower-hour (2.28 mg/J). These locomotives were permitted to run at 90 miles per hour (140 kilometers per hour), but they were alleged to have exceeded 100 miles per hour (160 kilometers per hour) several times. The heavy Class H Northerns of the Chicago and Northwestern Railroad were rebuilt in 1940 with lightweight rods, Boxpok driving wheels and roller bearings on all axles, and the boiler pressure was raised from 250 to 275 pounds per square inch (1,720 to 1,900 kilopascals). Some years later, 24 of them underwent another rebuild which included new nickel-steel frames, new cylinders, pilot beams and air reservoirs, new fireboxes and other minor improvements. These were reclassified as Class H-1.

Some Northern locomotives were also rebuilt from older engines. Between 1945 and 1947, the Reading Railroad rebuilt thirty of their heavy I-10 class 2-8-0 Consolidations to booster-fitted 4-8-4 Northern locomotives with 70 inches (1,778 millimeters) diameter driving wheels. An additional ring was added at the smokebox end of the boiler, which increased the length of the boiler tubes from 13 feet 6 inches (4.11 meters) to 20 feet (6.1 meters), and a larger smokebox was installed which increased the distance between the tube plate and the chimney center line from 34 inches (0.86 meters) to 111 inches (2.8 meters). Steam pressure was raised from 220 to 240 pounds per square inch (1,500 to 1,700 kilopascals). Four syphons were fitted, three in the firebox proper and one in the combustion chamber. A twelve-wheeled tender was attached, weighing 167 tons in working order, with a capacity of 23.5 tons of coal and 19,000 US gallons (72,000 liters) of water. A new cast-steel frame was used, with the cylinders cast integral and roller bearings on all axles. They were reclassified to T1 and numbered 2100 to 2129. Two of these locomotives, preserved for hauling special trains, were still in use in 1963.

Southern Pacific class GS-4
The Northerns were workhorses that went without much public recognition, with a few exceptions. The Class GS-4 Golden State locomotives of Southern Pacific (SP), of which 36 were built by Lima Locomotive Works in 1941 and 1942, were semi-streamlined and were given a striking livery with a broad orange valence over the wheels below a narrow red band that came halfway up the cab windows. The locomotives headed the Coast Daylight train on the railroad's Coast Line between Los Angeles and San Francisco. The television program The Adventures of Superman was introduced with a shot of an SP GS-4 as the announcer declared that Superman was "more powerful than a locomotive." One of them, GS-4 no. 4449, has been restored and is in operating condition.

Even after the demise of steam, the Northern type has been in the spotlight of publicity and, along with Union Pacific no. 844 of the Union Pacific FEF Series, have been the favored type to provide mainline excursions in the United States. The latter is the only steam locomotive of a Class I railroad never to have been retired.

North American Production List
Most North American 4-8-4s were built by ALCO, Lima and the Baldwin Locomotive Works, while Canadian National Railway's fleet was built by Montreal Locomotive Works. Only the Canadian Pacific Railway, the Norfolk and Western Railway, the St. Louis Southwestern Railway (Cotton Belt) and the Reading Railroad built their own.

The Northern type was used by 37 railroads in the Americas, including 31 railroads in the United States, three in Canada, one in Mexico and two in Brazil. In all, there were fewer than 1,200 locomotives of this type in North America, compared to the approximately 2,500 4-8-2 Mountain types and 6,800 4-6-2 Pacific types. By far the largest fleet was owned by the CN and its subsidiary, the Grand Trunk Western Railroad, with altogether 203 locomotives.

North American 4-8-4 Locomotive Operators
Railroad
Quantity:  Nickname:   Class:  Road numbers:  Builder:  Build year:  Notes: 

Northern Pacific Railway

Quantity: 48
Nickname: "Northerns"
Class:  A
Road numbers: 2600–2611
Builder: Alco
Build year: 1926
Class: A-2
Road numbers: 2650–2659
Builder: Baldwin
Build year: 1934
Class: A-3
Road numbers: 2660–2667
Builder: Baldwin
Build year: 1938
Class: A-4
Road numbers: 2670–2677
Builder: Baldwin
Build year: 1941
Class: A-5
Road numbers: 2680–2689
Builder: Baldwin
Build year: 1943

Atchison, Topeka and Santa Fe Railway
Quantity: 65

Nickname: "Northerns"
Class:  3751
Road numbers: 3751–3764
Builder: Baldwin
Build year: 1927–1929
Notes: 3751 is used as an excursion locomotive.
Class: 3765
Road numbers: 3765–3775
Builder: Baldwin
Build year: 1938
Class: 3776
Road numbers: 3776–3785
Builder: Baldwin
Build year: 1941
Class: 2900
Road numbers: 2900–2929
Builder: Baldwin
Build year: 1943–1944

Canadian National Railways

Quantity: 160
Nickname: "Confederations"
Class: U-2-a
Road numbers: 6100–6119
Builder: CLC
Build year: 1927
Class: U-2-b
Road numbers: 6120–6139
Builder: MLW
Build year: 1927
Class: U-2-c
Road numbers: 6140–6159
Builder: MLW
Build year: 1929
Class: U-2-d
Road numbers: 6160–6164
Builder: MLW
Build year: 1936
Class: U-2-e
Road numbers: 6165–6179
Builder: MLW
Build year: 1940
Class: U-2-f
Road numbers: 6180–6189
Builder: CLC
Build year: 1940
Class: U-2-g
Road numbers: 6200–6234
Builder: MLW
Build year: 1943
Class: U-2-h
Road numbers: 6235–6264
Builder: MLW
Build year: 1944
Class: U-4-a
Road numbers: 6400–6404
Builder: MLW
Build year: 1936
Notes: Streamlined

Grand Trunk Western (Canadian National subsidiary)
Quantity: 43

Nickname: "Confederations"
Class:  U-3-a
Road numbers: 6300–6311
Builder: Alco
Build year: 1927
Class: U-3-b
Road numbers: 6312–6336
Builder: Alco
Build year: 1942–1943
Class: U-4-b
Road numbers: 6405–6410
Builder: Lima
Build year: 1938
Notes: Streamlined

Delaware, Lackawanna and Western Railroad
Quantity: 55

Nickname: "Poconos"
Class: Q-1
Road numbers: 1501–1505
Builder: Alco
Build year: 1927
Class: Q-2
Road numbers: 1601–1620
Builder: Alco
Build year: 1929
Class: Q-3
Road numbers: 1621–1630
Builder: Alco
Build year: 1932
Class: Q-4
Road numbers: 1631–1650
Builder: Alco
Build year: 1934

Canadian Pacific Railway
Quantity: 2

Nickname: "Northerns"
Class:  K1a
Road numbers: 3100–3101
Builder: CP (Angus)
Build year: 1928

Chicago and North Western Railway

Quantity: 35
Nickname: "Northerns"
Class: H
Road numbers: 3001–3035
Builder: Baldwin
Build year: 1929
Notes: 24 rebuilt to H-1

Chicago, Rock Island and Pacific Railroad
Quantity: 85

Nickname: "Northerns" 
Class:  R-67
Road numbers: 5000–5064
Builder: Alco
Build year: 1929–1930
Class: R-67
Road numbers: 5100–5119
Builder: Alco
Build year: 1944, 1946

Denver and Rio Grande Western Railroad
Quantity: 19

Nickname: "Westerns"
Class: M-64
Road numbers: 1700–1713
Builder: Baldwin
Build year: 1929
Class: M-68
Road numbers: 1800–1804
Builder: Baldwin
Build year: 1938

Great Northern Railway
Quantity: 38

Nickname: "Northerns"
Class: S-1
Road numbers: 2550–2555
Builder: Baldwin
Build year: 1929
Class: S-2
Road numbers: 2575–2588
Builder: Baldwin
Build year: 1930

Chicago, Burlington and Quincy Railroad
Quantity: 36

Class: O-5
Road numbers: 5600–5607
Builder: Baldwin
Build year: 1930
Class: O-5a
Road numbers: 5608–5635
Builder: CB&Q
Build year: 1936–1940

Milwaukee Road
Quantity: 52

Nickname: "Northerns"
Class: S-1
Road number: 9700
Builder: Baldwin
Build year: 1930
Notes: Renumbered 250 in 1938.
Class: S-1
Road number: 251
Builder: MILW
Build year: 1938
Class: S-2
Road numbers: 201–240
Builder: Baldwin
Build year: 1937, 1940
Class: S-3
Road numbers: 260–269
Builder: Alco
Build year: 1943
Notes: No. 261 used as an excursion locomotive.

Nashville, Chattanooga and St. Louis Railway
Quantity: 25

Nickname: "Dixies"
Class:  J-2
Road numbers: 565–569
Builder: Alco
Build year: 1930
Class: J-3
Road numbers: 570–589
Builder: Alco
Build year: 1942

St. Louis Southwestern Railway
Quantity: 20

Nickname: "Northerns"
Class:  L1
Road numbers: 800–809
Builder: BLW
Build year: 1930
Class: L1
Road numbers: 810–819
Builder: SSW
Build year: 1937, 1942–1943

Southern Pacific
Quantity: 70

Nickname: "Golden States"
Class: GS-1
Road numbers: 4400–4409
Builder: Baldwin
Build year: 1930
Class: GS-2
Road numbers: 4410–4415
Builder: Lima
Build year: 1936
Class: GS-3
Road numbers: 4416–4429
Builder: Lima
Build year: 1937
Class: GS-4
Road numbers: 4430–4457
Builder: Lima
Build year: 1941
Notes: 4449 is the only surviving GS-4 and is used as an excursion locomotive.
Class: GS-5
Road numbers: 4458–4459
Builder: Lima
Build year: 1942
Class: GS-6
Road numbers: 4460–4469
Builder: Lima
Build year: 1943

Texas and New Orleans Railroad (Southern Pacific subsidiary)
Quantity: 4

Nickname: "Golden States"
Class: GS-1
Road numbers: 700–703
Builder: Baldwin
Build year: 1930

Timken Roller Bearing Company (demonstrator)

Quantity: 1
Road number: Timken 1111
Builder: Alco
Build year: 1930
Notes: to NP 2626, class A-1.

Wabash Railroad
Quantity: 25

Nickname: "Northerns"
Class: O-1
Road numbers: 2900–2924
Builder: Baldwin
Build year: 1930–1931

Lehigh Valley Railroad
Quantity: 37

Nickname: "Wyomings"
Class: T-1a
Road numbers: 5100–5110
Builder: Baldwin
Build year: 1931–1932
Class: T-2a
Road numbers: 5200–5210
Builder: Alco
Build year: 1931–1932
Class: T-2b
Road numbers: 5211–5220
Builder: Alco
Build year: 1943
Class: T-3
Road numbers: 5125–5129
Builder: Baldwin
Build year: 1934–1935

New York Central Railroad
Quantity: 28

Nickname: "Niagaras"
Class: HS-1a
Road number: 800
Builder: Alco
Build year: 1931
Class: S-1a
Road number: 6000
Builder: Alco
Build year: 1945
Class: S-1b
Road numbers: 6001–6025
Builder: Alco
Build year: 1945–1946
Class: S-2a
Road number: 5500
Builder: Alco
Build year: 1946

Chesapeake and Ohio Railway
Quantity: 15

Nickname: "Greenbriers"
Class:  J-3
Road numbers: 600–606
Builder: Lima
Build year: 1935, 1942
Class: J-3-A
Road numbers: 610–614
Builder: Lima
Build year: 1948
Notes: No. 614 is the last commercially built passenger steam locomotive in the U.S. and is currently the world's most advanced steam locomotive. It is now at the Greenbrier Hotel, awaiting service for the Greenbrier Presidential Express.

Ontario Northland Railway

Quantity: 5
Nickname: "Northerns"
Class: 1100
Road numbers: 1100–1104
Builder: CLC
Build year: 1936

Atlantic Coast Line Railroad

Quantity: 12
Nickname: "1800s"
Class: R-1
Road numbers: 1800–1811
Builder: Baldwin
Build year: 1938

Richmond, Fredericksburg and Potomac Railroad

Quantity: 27
Nickname: Generals
Road numbers: 551–555
Builder: 
Builder: Baldwin
Build year: 1937
Nickname: Governors
Road numbers: 601–612
Builder: Baldwin
Build year: 1938, 1942
Nickname: Statesmen
Road numbers: 613–622
Builder: Baldwin
Build year: 1944–1945

Toledo, Peoria and Western Railway

Quantity: 6
Nickname: "Northerns"
Class: H-10
Road numbers: 80–85
Builder: Alco
Build year: 1937

Union Pacific Railroad
Quantity: 45

Nickname: "Four-Eight-Fours"
Class: FEF-1
Road numbers: 800–819
Builder: Alco
Build year: 1937
Class: FEF-2
Road numbers: 820–834
Builder: Alco
Build year: 1939
Class: FEF-3
Road numbers: 835–844
Builder: Alco
Build year: 1944
Notes: 844 Is the oldest operating steam engine on a Class One Railroad and is used as an excursion locomotive.

Wisconsin Central Railway

Quantity: 4
Nickname: "Northerns"
Class: O-20
Road numbers: 5000–5003
Builder: Lima
Build year: 1938

Spokane, Portland and Seattle Railway
Quantity: 3

Nickname: "Northerns"
Class: E-1
Road numbers: 700–702
Builder: BLW
Build year: 1938
Notes: NP A-3 class; 700 survives and is used as an excursion locomotive.

Missouri Pacific Railroad

Quantity: 40
Nickname: "Northerns" 
Road numbers: 2101–2125
Builder: MP
Build year: 1940–1942
Road numbers: 2201–2215
Builder: Baldwin
Build year: 1943

Norfolk and Western Railway

Quantity: 14
Nickname: "J"s
Class:  J
Road numbers: 600–613
Builder: N&W
Build year: 1941–1950
Notes: 611 has been restored and returned to revenue service for excursions in the summer of 2015.

Central of Georgia Railway

Quantity: 8
Nickname: "Big Apples"
Class: K
Road numbers: 451–458
Builder: Lima
Build year: 1943

Delaware and Hudson Railroad

Quantity: 15
Nickname: "Northerns"
Class: K-62
Road numbers: 300–314
Builder: Alco
Build year: 1943

St. Louis – San Francisco Railway

Quantity: 25
Nickname: "Northerns"
Class: 4500
Road numbers: 4524
Builder: Baldwin
Build year: 1942–1943

Western Pacific Railroad
Quantity: 6

Nickname: "Northerns"
Class: GS-64
Road numbers: 481–486
Builder: Lima
Build year: 1943
Notes: SP GS-6

Reading Railroad
Quantity: 30

Nickname: "Northerns"
Class: T-1
Road numbers: 2100–2129
Builder: Reading
Build year: 1945–1947
Notes: Converted from Class I-10a 2-8-0 locomotives

Ferrocarriles Nacionales de México (NdeM)
Quantity: 32

Nickname: "Niágaras"
Class: QR-1
Road numbers: 3025–3056
Builder: Alco
Quantity: 16
Builder: Baldwin
Quantity: 16
Build year: 1946

Western Maryland Railway

Quantity: 12
Nickname: "Potomacs"
Class:  J-1
Road numbers: 1401–1412
Builder: Baldwin
Build year: 1947

4-8-4s in Canada
Since the Canadian mainlines were generally laid with 115 pounds per yard (57 kilograms per meter) rail, Canadian 4-8-4s were heavy and weighed in with axle loads up to 31.3 short tons (28.4 tonnes).

When the Canadian National Railway (CN) introduced its first 4-8-4 in 1927, it used the name "Confederation" for the type, to celebrate the 60th anniversary of the Canadian Confederation. The CN employed a total of 160 Confederation locomotives.
Altogether, forty locomotives were delivered in 1927, twenty Class U-2-a from the Canadian Locomotive Company and twenty Class U-2-b from the Montreal Locomotive Works (MLW).

Another twenty Class U-2-c came from MLW in 1929 and another five Class U-2-d, also from MLW, in 1936.

The CN U-4a was one of the few streamlined Confederation types, with five locomotives built by MLW and also introduced in 1936. U-4a no. 6400 achieved fame in 1939 by heading the Royal Train and being exhibited at the New York World's Fair in the same year.

Between 1940 and 1944, a total of ninety more Confederation locomotives, built in four batches, were added to the CN roster.[8]The Canadian Pacific Railway (CPR) experimented with the 4-8-4 wheel arrangement in 1928, when two K-1a class locomotives were built in its Angus shops in Montreal, the first locomotives to be built with a one-piece cast-steel frame in Canada. However, since the CPR mainlines were built to high standards, the railway preferred to develop the 4-6-4 Hudson type for passenger work since it gave adequate power and was cheaper to maintain, while a ten-coupled type, the 2-10-4 Selkirk, was adopted for heavy-duty work. Nevertheless, although the two CPR Northerns remained orphans, they proved their worth continuously for 25 years on overnight passenger trains between Montreal and Toronto. Before their retirement in 1960, they were converted to oil-burners and worked freight trains in the prairie provinces.

Preservation by Country

In many countries, the 4-8-4 was a late development of the steam locomotive, close to the time of steam's demise. Many more were therefore preserved than of other older wheel arrangements, either plinthed or in museums, with several being kept in running condition. Some of the more notable preserved Northerns world-wide are listed here by country of origin.

United States
Atchison, Topeka & Santa Fe 2903: Illinois Railway Museum, Union, Illinois.
Atchison, Topeka & Santa Fe 2912: On static display in Pueblo, Colorado, awaiting cosmetic restoration.
Atchison, Topeka & Santa Fe 2913: On static display in Fort Madison, Iowa.
Atchison, Topeka & Santa Fe 2921: Beard Brook Park, Modesto, California.
Atchison, Topeka & Santa Fe 2925: California State Railroad Museum, Sacramento, California.
Atchison, Topeka & Santa Fe 2926: Currently under restoration for excursion service in Albuquerque at a site leased from the GSA near 8th Street and Haynes Avenue, due to be completed in 2015 and may be available for tour and close inspection. More information at New Mexico Steam Locomotive and Railroad Historical Society.
Atchison, Topeka & Santa Fe 3751: Restored in 1991, owned by the San Bernardino Railroad Historical Society and is operated in excursion service. She is the oldest surviving 4-8-4, the first one to be built by the Baldwin Locomotive Works and the first 4-8-4 to be built for the Santa Fe.
Atchison, Topeka & Santa Fe 3759: On Display in Kingman, Arizona.
Atchison, Topeka & Santa Fe 3768: On display at the Great Plains Transportation Museum in Wichita, Kansas.
Chesapeake & Ohio 614: Restored in 1980 and again in 1995, owned by Iron Horse Enterprise, Clifton Forge, Virginia.
Chicago, Burlington and Quincy Railroad 5614: Patee Park, St. Joseph, Missouri.
Chicago, Burlington and Quincy Railroad 5629: Colorado Railroad Museum, Golden, Colorado.
Chicago, Burlington and Quincy Railroad 5631: Rotary Park, Sheridan, Wyoming.
Chicago, Burlington and Quincy Railroad 5633: Douglas Railroad Interpretive Center, Douglas, Wyoming.
Grand Trunk Western 6323: Illinois Railway Museum in Union, Illinois.
Great Northern Railway S-2 No.2584: On display at the Havre, Montana depot.
Milwaukee Road 261: Restored in 1993, owned, maintained, and operated by the Friends of the 261 in Minneapolis, Minnesota.
Milwaukee Road 265: Illinois Railway Museum in Union, Illinois.
Nashville, Chattanooga, & St. Louis 576 Centennial Park, Nashville, Tennessee.
Norfolk & Western 611: Ran frequent excursions in the 1980s and early 1990s, then placed on static display at the Virginia Museum of Transportation, Roanoke, Virginia. Second restoration to operational condition completed June 2015 at the North Carolina Transportation Museum, Spencer, North Carolina.
Reading 2100: Restored in 1988 and 1998, converted to burn oil in the Early 2000s. On long-term lease to the American Steam Railroad. Currently being moved to Cleveland, Ohio for restoration.
Reading 2101: B&O Railroad Museum, Baltimore, Maryland.
Reading 2102: Reading & Northern Railroad, Port Clinton, Pennsylvania.
Reading 2124: Used on the "Reading Rambles" in the late 1950s and 1960s. On static display at Steamtown National Historic Site in Scranton, Pennsylvania.
St. Louis Southwestern 819: Built in 1943, it was the last locomotive built by the Cotton Belt. Restored to service in 1986 and housed at the Arkansas Railroad Museum in Pine Bluff, Arkansas.
St. Louis-San Francisco Railway 4500: As the Frisco Meteor, ran overnight passenger service between St. Louis, Tulsa and Oklahoma City. Cosmetically restored and relocated to Route 66 Station Park in Tulsa, OK in 2011.
St. Louis-San Francisco Railway 4501: Built in 1942, ran overnight passenger service as the Frisco Meteor between St. Louis, Tulsa, and Oklahoma City. Donated to the Dallas Museum of the American Railroad in September 1964.
St. Louis-San Francisco Railway 4516: Missouri State Fairgrounds, Sedalia, Missouri.
St. Louis-San Francisco Railway 4524: Grant Beach Park, Springfield, Missouri.
Spokane, Portland and Seattle 700: Restored in 1990 by the Oregon Rail Heritage Foundation, and is operated in excursion service. No. 700 is stored at the Oregon Rail Heritage Center in Portland, Oregon, along with SP 4449.
Southern Pacific 4449: Still in operation, served as the locomotive for the Bicentennial American Freedom Train. Stored at the Oregon Rail Heritage Center in Portland, Oregon along with SPS 700.
Southern Pacific 4460: On static display at the Museum of Transportation in St. Louis, Missouri. This was the last steam locomotive used in revenue service by SP.
Union Pacific 814: Rock Island Depot Museum, Council Bluffs, Iowa.
Union Pacific 833: Utah State Railroad Museum, Ogden, Utah.
Union Pacific 838: Union Pacific Railroad, Cheyenne, Wyoming.
Union Pacific 844: The last steam locomotive built for Union Pacific Railroad (12/1944). Part of UP heritage fleet, often used for running in excursion service, and on occasion revenue service. Never retired, longest continuously operating steam locomotive on a Class 1 Railroad. Kept at Cheyenne, Wyoming when not on excursion.

Canada
CN 6153: On static display at the Canadian Railway Museum in Delson, Quebec.
CN 6167: On static display in downtown Guelph, Ontario.
CN 6200: Canadian Science & Technology Museum, Ottawa, Ontario.
CN 6213: On static display in downtown Toronto, Ontario, at the Toronto Railway Heritage Centre.
CN 6218: Fort Erie Railroad Museum, Fort Erie, Ontario. Used by the CN on excursions in the 1960s and 1970s.
CN 6400: Canadian Science & Technology Museum, Ottawa, Ontario.
CPR 3100: Canadian Science & Technology Museum, Ottawa, Ontario.
CPR 3101: On display at EVRAZ (formerly IPSCO Steel), Regina, Saskatchewan.
GTW 6323: On display at the Illinois Railway Museum in Union, Illinois.
GTW 6325: Restored in 2001 by the Ohio Central Railroad, owned by Age of Steam Roundhouse, Sugarcreek, Ohio. Currently, the locomotive is in need of valve and running gear work.

4-8-4 (Northern) Overview
Equivalent classifications
UIC class: 2D2
French class: 242
Turkish class: 48
Swiss class: 4/8
Russian class: 2-4-2
First known tender engine version
First use: 1926
Country: United States of America
Locomotive: NP class A
Railroad: Northern Pacific Railway
Designer: American Locomotive Company
Builder: American Locomotive Company
Evolved from: 4-8-2

See also:

Steam Locomotives

C&O 614 at the C&O Historical Society’s “Steam Under the Stars” in Clifton Forge, VA,  June 18, 2011.

By jpmueller99 from Shenandoah Valley of VA, USA (C&O 614  Uploaded by AlbertHerring) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

A 4-8-4 Slideshow.

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Diagram of two small leading wheels, four large driving wheels joined by a coupling rod, and two small trailing wheels.

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Diagram of two small leading wheels, four large driving wheels joined by a coupling rod, and two small trailing wheels.

C&O 614 at the C&O Historical Society’s “Steam Under the Stars” in Clifton Forge, VA, June 18, 2011.
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