A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material to heat water in the locomotive's boiler to the point where it becomes gaseous and its volume increases 1,700 times. Functionally, it is a steam engine on wheels.
A Fairlie locomotive is a type of articulated steam locomotive that has the driving wheels on bogies. The locomotive may be double-ended or single ended. Most double-ended Fairlies had wheel arrangements of 0-4-4-0T or 0-6-6-0T.
A tank locomotive is a steam locomotive which carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers to hold fuel; in a tender-tank locomotive a tender holds some or all of the fuel, and may hold some water also.
Under the Whyte notation for the classification of steam locomotives, a 2-10-4 locomotive has two leading wheels on one axle, usually in a Bissel truck, ten coupled driving wheels on five axles, and four trailing wheels on two axles, usually in a bogie. 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.
A 2-8-8-4 steam locomotive, under the Whyte notation, has two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck. The type was generally named the Yellowstone, a name given it by the first owner, the Northern Pacific Railway, whose lines ran near Yellowstone National Park. Seventy-two Yellowstone-type locomotives were built for four U.S. railroads.
Main components found on a typical steam locomotive include:
In the Whyte notation, a 6-2-0 is a railroad steam locomotive that has an unpowered three-axle leading truck followed by a single powered driving axle. This wheel arrangement is associated with the Crampton locomotive type, and in the USA the single class were sometimes referred to as Cramptons.
In a steam engine, the firebox is the area where the fuel is burned, producing heat to boil the water in the boiler. Most are somewhat box-shaped, hence the name. The hot gases generated in the firebox are pulled through a rack of tubes running through the boiler.
The M1 was a class of steam locomotive of the Pennsylvania Railroad (PRR). It was a class of heavy mixed-traffic locomotives of the 4-8-2 "Mountain" arrangement, which uses four pairs of driving wheels with a four-wheel guiding truck in front for stability at speed and a two-wheel trailing truck to support the large firebox needed for sustained power. Although built for both passenger and freight work, they spent most of their service lives hauling heavy high-speed freight trains. Many PRR men counted the M1 class locomotives as the best steam locomotives the railroad ever owned.
The three L-10-8-8-0 Mallet steam locomotives of the Erie Railroad, built in July 1907 by ALCO, and numbered 2600, 2601 and 2602 ; were unique in that they were the only articulated camelback locomotives ever built.
A camelback locomotive is a type of steam locomotive with the driving cab placed in the middle, astride the boiler. Camelbacks were fitted with wide fireboxes which would have severely restricted driver visibility from the normal cab location at the rear.
The Pennsylvania Railroad's S2 class was a steam turbine locomotive designed and built in a collaborative effort by Baldwin Locomotive Works and Westinghouse Electric & Manufacturing Company, as an attempt to prolong the dominance of the steam locomotive by adapting technology that had been widely accepted in the marine industry. One was built, #6200, delivered in September 1944. The S2 was the sole example of the 6-8-6 wheel arrangement in the Whyte notation, with a six-wheel leading truck keeping the locomotive stable at speed, eight powered and coupled driving wheels, and a six-wheel trailing truck supporting the large firebox. The S2 used a direct-drive steam turbine provided by the Westinghouse Electric & Manufacturing Company, geared to the center pair of axles with the outer two axles connected by side rods; the fixed gear ratio was 18.5:1. Such design was to prevent energy loss and S2 achieved a mechanical efficiency of 97% which means only 3% of steam energy was lost within the propulsion equipment. The disadvantage of a direct-drive steam turbine was that the turbine could not operate at optimal speeds over the locomotive's entire speed range. The S2 was the largest, heaviest and fastest direct-drive turbine locomotive design ever built.
On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, a booster engine was mounted on the trailing truck to provide extra tractive effort when starting a heavy train and at low speeds on gradients.
Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck.
Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and four trailing wheels.
The term cab forward locomotive refers to various rail and road vehicle designs that place the driver's compartment substantially farther towards the front than is common practice.
The Pennsylvania Railroad class Q1, #6130, was a single experimental steam locomotive designed for dual service. The locomotive entered service in 1942, and retired in 1949 after accumulating a relatively low 165,000 service miles.
The South African Railways Class 16DA 4-6-2 of 1930 is a class of steam locomotives.
Central Railroad of New Jersey No. 113, also known as CNJ No. 113, is an 0-6-0 "Switcher" type steam locomotive originally built in June of 1923 by the American Locomotive Company (ALCO) for the Central Railroad of New Jersey. The locomotive was designed solely for yard service and could only operate at slow speeds due to the locomotive not having any leading or trailing wheels, but only six driving wheels. No. 113 currently performs passenger excursion services and some freight assignments on Reading Blue Mountain & Northern operated tracks. It is owned and operated by the Railway Restoration Project 113 Organization out of Minersville, PA.
Reading 1187 is a camelback 0-4-0 switcher locomotive built in 1903 by Baldwin for the Philadelphia and Reading Railroad. It was primarily used for yard switching services, until 1946, when it was sold to the Colorado Fuel and Iron Company's E&G Brooke Plant as No. 4. In 1962, it made its way to the Strasburg Rail Road in Strasburg, Pennsylvania to be used in hauling tourist trains, but due to its small size, it was reassigned to switching passenger cars. After being removed from service in 1967, No. 1187 sat on display at the Railroad Museum of Pennsylvania, before sitting idle at the Strasburg yard. In 2020, it was acquired by the Age of Steam Roundhouse, who is currently giving the locomotive a cosmetic stabilization at their location in Sugarcreek, Ohio.
