Atchison, Topeka & Santa Fe Railway 2-10-4 steam locomotive No. 5000 "Madame Queen" waiting in a siding to meet an

eastbound train at Ricardo, New Mexico, March 1943.

(Jack Delano, working for the US Farm Security Administration - Office of War Information, Public domain, via Wikimedia Commons)



Under the Whyte notation for the classification of steam locomotives, a 2-10-4 locomotive has two leading wheels on one axle, ten coupled driving wheels on five axles, and four trailing wheels on two axles, usually in a truck. These were referred to as the Texas type in most of the United States, the Colorado type on the Burlington Route, and the Selkirk type in Canada.


Texas & Pacific Steam Locomotive No. 610 in Palestine, Texas.

(Renelibrary, CC BY-SA 4.0 <>, via Wikimedia Commons)



The 2-10-4 Texas wheel arrangement originated and was principally used in the United States. The evolution of this locomotive type began as a 2-10-2 Santa Fe type with a larger four-wheeled trailing truck that would allow an enlarged firebox. A subsequent development was as an elongated 2-8-4 Berkshire type that required extra driving wheels to remain within axle load limits. Examples of both of these evolutionary progressions can be found.

Some 2-10-4 tank locomotives also existed in eastern Europe. One extraordinary experimental 2-10-4 tender locomotive, built in the Soviet Union, had an opposed-piston drive system.


Vaughn, New Mexico. One of the 5000 Class Atchison, Topeka and Santa Fe Railway freight locomotives about to leave on the run to Clovis, New Mexico.

(Jack Delano, Public domain, via Wikimedia Commons



United States

Atchison, Topeka and Santa Fe Railway
The Atchison, Topeka and Santa Fe Railway (ATSF) took delivery of locomotive No. 3829 from the Baldwin Locomotive Works in 1919. It was used by ATSF as an experimental locomotive and was rostered as a member of ATSF's 3800 class of 2-10-2s that was fitted with a four-wheel trailing truck. Nearly 100 more 3800 class locomotives were delivered after No. 3829, but all with the 2-10-2 wheel arrangement. Photographs exist that show No. 3829 fitted with at least two different designs of four-wheel trailing truck through the years. No other members of the 3800 class have been documented with four-wheel trailing trucks. No. 3829 was scrapped in 1955, still equipped with a four-wheel trailing truck.

Santa Fe, which had originated the 2-10-4 type, adopted it again in 1930 with No. 5000, named Madame Queen (see top photo). This locomotive was similar to the C&O T-1, with the same 69 in (1,750 mm) drivers, but with 300 psi (2.1 MPa) boiler pressure and 60% limited cutoff. It proved the viability of the type on the ATSF, but the Great Depression shelved plans to acquire more.

In 1938, with the railroad's fortunes improving, ATSF acquired 10 more 2-10-4 locomotives. These came with 74 in (1,880 mm) diameter drivers and 310 psi (2.1 MPa) boiler pressure, making these ATSF 2-10-4s the fastest and most modern of all.

Of the original order of ten, five were oil-burning and five coal-burning, but when Santa Fe ordered 25 more for delivery in 1944, all were delivered equipped to burn oil. The first of the 1944 batch produced 5,600 drawbar horsepower (4.2 MW) on road test, the highest figure known for a two-cylinder steam locomotive.

Texas and Pacific
The 2-10-4 type was revived in 1925 by the Lima Locomotive Works. This time, it was an expansion of the 2-8-4 Berkshire type that Lima had pioneered. A version of the Berkshire with 10 driving wheels instead of eight was an obvious development and the first to be delivered were to the Texas and Pacific Railway, after which the type was subsequently named. The four-wheel trailing truck allowed a much larger firebox, thus a greater ability to generate heat, and thus steam. The Superpower design, as Lima's marketing department called it, resulted in a locomotive that could develop great power at speed while not running out of steam-generating ability.

Bessemer and Lake Erie
Baldwin built a fleet of 47 H-1 class 2-10-4s for the Bessemer and Lake Erie Railroad, an iron ore–hauling railroad, between 1929 and 1944, in eight subclasses numbered 601–647. Calculated tractive force was 102,106 lbf (454.19 kN), average weight was over 500,000 lb (230 t), and boiler pressure was 250 psi (1.7 MPa). Eighteen were sold in 1951 to the Duluth, Missabe and Iron Range Railway, another ore-hauling railroad, that renumbered them 700–717. By the beginning of the 1960s, all but one were sold for scrap. The exception was No. 643, which almost operated in excursion service in the late 1990s, but for its large size. It is now owned by the Age of Steam Roundhouse.

Chesapeake and Ohio
The early Lima-built Texas types were low-drivered, 60 to 64 in (1,520 to 1,630 mm) in diameter, which did not leave enough space to fully counterweight the extremely heavy and sturdy side rods and main rods required for such a powerful locomotive's piston thrusts. That changed in 1930 on the Chesapeake and Ohio Railway (C&O), which stretched the design of an Erie Railroad high-driver Berkshire type locomotive to produce 40 of the C&O T-1, a Texas type with 69 in (1,750 mm) diameter drivers that was both powerful and fast enough for the new higher-speed freight services that the railroads were introducing. All subsequent Texas types were of this higher-driver sort.

Pennsylvania Railroad
The Pennsylvania Railroad (PRR) ordered few new locomotives after 1930, since electrification both consumed the railroad's resources and resulted in a supply of excess steam locomotives that eliminated any requirement for new power. Until the Second World War had begun, the PRR's locomotive fleet had not begun to appear inadequate. Although the PRR urgently needed new and modern freight power, the War Production Board prohibited working on a new design, and not enough time remained to trial a prototype in any event, the PRR cast around for other railroads' designs that it might modify for PRR use.

It settled on the C&O's T-1. Some modifications were made to the design for these PRR "War Babies". These included PRR drop-couplers, sheet-steel pilots, PRR-style cabs, large PRR tenders, Keystone number plates up front, and other modifications. It still betrayed its foreign heritage by lacking the PRR trademark Belpaire firebox and by having a booster engine on the trailing truck. Altogether, 125 locomotives were built between 1942 and 1944 and became the largest fleet of Texas-type locomotives in existence. All were eventually sold as scrap when the Pennsylvania Railroad converted to diesel.


Canadian Pacific Selkirk class 5927 takes on oil at the South Edmonton shops.

(gordon hunter, CC BY-SA 2.0 <>, via Wikimedia Commons)



The Canadian Pacific (CP) Selkirk locomotives were all built by Montreal Locomotive Works (MLW). The first 20 of these large engines were built in 1929, designated T1a class and allocated numbers 5900 to 5919. Their Canadian type name was after the Selkirk Mountains across which they were placed in service, the railway summit of which was located just inside the western portal of the Connaught Tunnel beneath Rogers Pass.

MLW built another 10 of these successful locomotives for CP during November and December 1938, designated T1b class and numbered from 5920 to 5929. Modifications to the original design led to the T1b being 11 tons lighter while its operating steam pressure was increased from 275 to 285 psi (1,900 to 1,970 kPa).

A further six Selkirks, classed T1c and numbered from 5930 to 5935, were delivered by MLW in 1949. They were the last standard gauge steam locomotives to be built in Canada for a Canadian railway. These were very similar to the T1b class, apart from a few refinements, which included two cross-compound air compressors to speed up recharging of the air brake system, while some small streamlining touches were not retained, such as the streamlined casing around the smokebox stack and the teardrop shape of the classification lights. In addition, the insides of the cabs were no longer insulated in the same manner as the previous versions, which had provided better cold-weather cab insulation and were better liked by crews. The last Selkirks were taken out of service in 1959. These were the most powerful steam locomotives in the British Empire.


Locomotive 611, Texas and Pacific Railway Company, ca. 1946.

(Robert Yarnall Richie, No restrictions, via Wikimedia Commons)



Equivalent classifications
UIC class: 1E2, 1′E2′
French class: 152
Turkish class: 58
Swiss class: 5/8
Russian class: 1-5-2
First known tender engine version
First use: 1919
Country: United States
Locomotive: No. 3829
Railway: Atchison, Topeka and Santa Fe Railway
Designer: Baldwin Locomotive Works
Builder: Baldwin Locomotive Works
Evolved: from 2-10-2, 2-8-4


Diagram of the 2-10-4 wheel arrangement. Front of locomotive is at left.

(Gwernol, Public domain, via Wikimedia Commons)