The New York Central Railroad (NYC) called the 4-8-2 type of steam locomotive the Mohawk type. It was known as the Mountain type on other roads, but the New York Central did not see the name as fitting on its famous Water Level Route. Instead, it picked the name of one of those rivers its rails followed, the Mohawk River, to name its newest type of locomotive.
The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. It can also serve as a reversing gear. It is sometimes referred to as the "motion".
The Pennsylvania Railroad K4 was a class of 425 4-6-2 steam locomotives built between 1914 and 1928 for the PRR, where they served as the primary main line passenger steam locomotives on the entire PRR system until late 1957.
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 Pennsylvania Railroad (PRR) class T1 duplex-drive 4-4-4-4 steam locomotives, introduced in 1942 with two prototypes and later in 1945-1946 with 50 production examples, were the last steam locomotives built for the PRR and arguably its most controversial. They were ambitious, technologically sophisticated, powerful, fast and distinctively streamlined by Raymond Loewy. However, they were also prone to wheelslip both when starting and at speed, in addition to being complicated to maintain and expensive to run. The PRR decided in 1948 to place diesel locomotives on all express passenger trains, leaving unanswered questions as to whether the T1's flaws were solvable, especially taking into account that the two prototypes did not have the problems inherent to the production units.
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.
The PRR S1 class steam locomotive was a single experimental duplex locomotive of the Pennsylvania Railroad. It was designed to demonstrate the advantages of duplex drives espoused by Baldwin Chief Engineer Ralph P. Johnson. The S1 class was the largest steam locomotive ever built. The streamlined Art Deco styled shell of the locomotive was designed by Raymond Loewy.
The Caprotti valve gear is a type of steam engine valve gear invented in the early 1920s by Italian architect and engineer Arturo Caprotti. It uses camshafts and poppet valves rather than the piston valves used in other valve gear. While basing his design on automotive valves, Caprotti made several significant departures from this design to adapt the valves for steam. Having agreed a joint-venture with Worcester-based engineering company Heenan & Froude from 1938, Heenan & Froude fully acquired Caprotti post-World War II in 1947.
British Railways built twenty locomotives of the LMS Stanier Black Five type, fitted with Caprotti valve gear, in 1948; the BR Caprotti Black Fives. These were numbered 44738-57, 44686 and 44687. The Black Fives had been fitted with Walschaerts valve gear as standard. In 1947, as part of an experimental programme by George Ivatt to try to improve the already good design, (4)4767 was built with Stephenson link motion. The Caprotti-fitted Black Fives were part of the same programme.
The NZR K class of 1932 was a class of mixed traffic 4-8-4 steam locomotives built by the New Zealand Railways Department (NZR) that operated on New Zealand's railway network. The locomotives were developed following the failure of the G class Garratt locomotives. The class should not be confused with the much earlier K class of 1877-78, the first American-built engines to arrive in New Zealand.
The Franco–Crosti boiler is a type of boiler used for steam locomotives. It was designed in the 1930s by Attilio Franco and Dr Piero Crosti. The main difference between it and conventional feedwater heaters widely used on the continent is that the Franco-Crosti boiler uses both exhaust steam and exhaust gases from the firebox. Conventional feedwater heaters only use exhaust steam.
Class E6 on the Pennsylvania Railroad was the final type of 4-4-2 "Atlantic" locomotive built by the railroad, and second only to the Milwaukee Road's streamlined class A in size, speed and power. Although quickly ceding top-flight trains to the larger K4s Pacifics, the E6 remained a popular locomotive on lesser services and some lasted to the end of steam on the PRR. One, #460, called the Lindbergh Engine, is preserved at the Railroad Museum of Pennsylvania. It was moved indoors to begin preparations for restoration on March 17, 2010. On January 10, 2011, PRR #460 was moved to the museum's restoration shop for a two- to three-year project, estimated to cost $350,000. The engine is listed in the National Register of Historic Places.
Pennsylvania Railroad Class L1s were 2-8-2 "Mikado"-type steam locomotives that were used on the Pennsylvania Railroad during the early twentieth century. These 574 locomotives were manufactured between 1914 and 1919 by the railroad's own Juniata Shops as well as the Baldwin Locomotive Works (205) and the Lima Locomotive Works (25).
Southern Railway 1401 is a 4-6-2 steam locomotive built in July 1926 by the American Locomotive Company (ALCO) of Richmond, Virginia, for the Southern Railway (SOU) as a member of the Ps-4 class, which was based on the United States Railroad Administration (USRA) Heavy Pacific design with some minor differences. It was assigned to haul SOU's premier mainline passenger trains between Washington, D.C., and Atlanta, Georgia.
The PRR J1 was a class of 2-10-4 "Texas" type steam locomotives built between 1942 and 1944. The J1 had over 95,000 pounds-force (422.6 kN) of tractive effort, plus an additional 15,000 lbf (66.7 kN) if the booster engine was used.
The South African Railways Class 10B 4-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal.
The South African Railways Class 10A 4-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal.
The Southern Railway Ps-4 was a class of 4-6-2 steam locomotives built for the Southern Railway, as well as its subsidiaries, the Alabama Great Southern Railroad and the Cincinnati, New Orleans and Texas Pacific Railway. The locomotives were notable for their green with gold trim liveries, and have been regarded by Smithsonian curator John H. White Jr. as being "among the most celebrated passenger locomotives operated in the United States...."
Pennsylvania Railroad 5550 is a mainline duplex drive steam locomotive under construction in the United States. With an estimated completion by 2030, the locomotive will become the 53rd example of the Pennsylvania Railroad's T1 steam locomotive class and the only operational locomotive of its type, as well as the largest steam locomotive built in the United States since 1952. The estimated cost of PRR 5550 was originally $10 million, but an updated projected cost of $7 million was released with the acquisition of an existing long-haul tender from the Western New York Railway Historical Society in August 2017. Construction began in 2014 with the casting of the locomotive's keystone-shaped number plate. As of February 2024 the locomotive was 43% complete.
The Pennsylvania Railroad's class K29s comprised a single experimental 4-6-2 "Pacific" type steam locomotive. Constructed by Alco-Schenectady, it was given road number 3395. Although only one demonstrator was constructed, the K29s would become the basis for the highly successful K4s Pacifics and L1s Mikados. The lone example spent most of its life on the PRR's Pittsburgh division main line and was retired around 1929.
