Instruct: Given a question, retrieve documents that can help answer the question.
Query: What was the fastest steam locomotive?
London and North Eastern Railway locomotive numbered 4468 Mallard is a Class A4 4-6-2 Pacific steam locomotive built at Doncaster Works, England in 1938. It is historically significant as the holder of the world speed record for steam locomotives at 126mph (203km/h).[1]
The fuel used depended on what was economically available to the railway. In the UK and other parts of Europe, plentiful supplies of coal made this the obvious choice from the earliest days of the steam engine. Until 1870,[24] the majority of locomotives in the United States burned wood, but as the Eastern forests were cleared, coal gradually became more widely used until it became the dominant fuel worldwide in steam locomotives. Railways serving sugar cane farming operations burned bagasse, a byproduct of sugar refining. In the US, the ready availability and low price of oil made it a popular steam locomotive fuel after 1900 for the southwestern railroads, particularly the Southern Pacific. In the Australian state of Victoria, many steam locomotives were converted to heavy oil firing after World War II. German, Russian, Australian and British railways experimented with using coal dust to fire locomotives.
If running is achieved, "Tornado" would also become the second fastest operational steam locomotive in the world. Regular steam operation was last seen in Britain in 1967 with the Merchant Navy class Pacific locomotives operating on the Waterloo to Bournemouth route. The fastest operational steam locomotive in the world is Deutsche Reichsbahn 18.201, allowed to run in Germany up to .
Specially modified R class steam locomotives were also used to operate a Saturday return service, becoming the fastest regular steam hauled passenger service in the world. R711 entered service on regular trains on 21 November 1998 and was fitted with multiple unit control equipment for diesel electric locomotives.
Unlike other railroads at Disneyland-style parks, where the trains are powered by actual steam locomotives, Hong Kong Disneyland's trains are powered by steam-outline locomotives, which are diesel locomotives with the outward appearance of steam locomotives. This means that the tenders are the real locomotives that haul the trains, as they contain the prime mover, traction motors, diesel fuel and generators that supply electricity to the rest of the train. This is due to Hong Kong's strict emissions standards, which also served as a cost-effective measure which obviated the need to build new steam locomotives, or the finding and transport to Hong Kong of suitable existing narrow gauge steam locomotives. As a result, in order to mimic the sound of an actual steam locomotive, typical steam audio (chuffing, steam whistle, etc.) are emitted from a set of hidden speakers installed on each locomotive. Despite the fact that they are not steam-powered, Dana Amendola, the author of "All Aboard: The Wonderful World of Disney Trains", describes the locomotives as "a representation of the golden age of railroading."
A steam turbine locomotive is a steam locomotive which transmits steam power to the wheels via a steam turbine. Numerous attempts at this type of locomotive were made, mostly without success. In the 1930s this type of locomotive was seen as a way both to revitalize steam power and challenge the diesel locomotives then being introduced.
There are two ways to drive the wheels: either directly via gears, or using generator-driven traction motors.
The most famous steam locomotive operating on the British main line is the 1923 built "Flying Scotsman". After being taken into public ownership in 2004, following a decade long refit it returned to mainline service in 2016. The fastest steam locomotive ever built, the 1938 built "Mallard", was also certified for main line operation briefly in the 1980s.
Placing what was termed as "the biggest British loco order since steam days", EWS placed an order for 250 units in May 1996 to be built at the EMD plant in London, Ontario, Canada at a cost of £375 million. Financed by Locomotion Capital (later Angel Trains), the first locomotives were ready in early 1998; the fastest delivery of an all-new locomotive type by GM. 
The visual styling of the new trainsets made the existing fleets of locomotives and railcars suddenly look old hat. Rail lines soon responded by adding streamlined shrouding and varying degrees of mechanical improvement to older locomotives, and re-styling heavyweight cars. The first American steam locomotive to receive that treatment was one of the New York Central Railroad's J-1 Hudson class locomotives built in 1930, which was re-introduced with streamlined shrouding and dubbed the "Commodore Vanderbilt" in December 1934. New York Central's streamline styling was designed by Henry Dreyfuss, who followed his work on the "Vanderbilt" with full-length exterior and interior design of NYC's "Mercury" trainsets in 1936. 1937 saw bullet-front streamlining introduced by Otto Kuehler on a 4-6-2 locomotive for B&O's "Royal Blue", with a variation of that theme used by Dreyfuss on NYC's new J-3a Hudsons for the "Twentieth Century Limited." While streamlining on steam locomotives was more about marketing than performance, newly designed locomotives with state-of-the-art steam technology became very fast. The Milwaukee Road class A Atlantics, purpose-built to compete with the "Twin Cities Zephyr" in 1935, were the first "steamliners" equipped to back up their styled claim to extra speed. During a run by locomotive #2 with a dynamometer car on May 15, 1935, a top speed of 112.5 mph (181.1 km/h) was recorded. This was the fastest authenticated speed reached by a steam locomotive at the time, making #2 the rail speed record holder for steam and the first steam locomotive to top 110 mph (177 km/h). That record lasted until a German DRG Class 05 locomotive exceeded it the following year. In 1937 Milwaukee introduced the class F7 Hudsons on the "Twin Cities Hiawatha" run, which were known to cruise above and said to exceed on occasion. The Milwaukee Road's speedsters were designed by Otto Kuehler with "shovel nose" styling and for the Class A some details evocative of the "Zephyrs." Streamliner steam locomotives continued to be produced into the early postwar era; among the most distinctive were Pennsylvania Railroad's duplex-drive 6-4-4-6 type S1 and 4-4-4-4 type T1 locomotives styled by Raymond Loewy. In terms of service longevity, the most successful were the Norfolk and Western J1 class locomotives introduced in 1941. 
The way the valve controlled the steam entering and leaving the cylinder was known as steam distribution and shown by the shape of the indicator diagram. What happened to the steam inside the cylinder was assessed separately from what happened in the boiler and how much friction the moving machinery had to cope with. This assessment was known as "engine performance" or "cylinder performance". The cylinder performance, together with the boiler and machinery performance, established the efficiency of the complete locomotive. The pressure of the steam in the cylinder was measured as the piston moved and the power moving the piston was calculated and known as cylinder power. The forces produced in the cylinder moved the train but were also damaging to the structure which held the cylinders in place. Bolted joints came loose, cylinder castings and frames cracked and reduced the availability of the locomotive.
The fastest steam locomotive
Locomotive 498.106 ČSD, nicknamed Albatross, reached top speed 162 km/h on railway test circuit Velim (August 27, 1964)
New steam locomotives were built in India well into the early 1970s; the last broad-gauge steam locomotive to be manufactured, Last Star, a WG-class locomotive (No.10560) was built in June 1970, followed by the last meter-gauge locomotive in February 1972.[91] Steam locomotion continued to predominate on Indian Railways through the early 1980s; in fiscal year 1980–81, there were 7,469 steam locomotives in regular service, compared to 2,403 diesels and 1,036 electrics.[92] Subsequently, steam locomotion was gradually phased out from regular service, beginning with the Southern Railway Zone in 1985; the number of diesel and electric locomotives in regular service surpassed the number of steam locomotives in service in 1987–88.[93] All regular broad-gauge steam service in India ended in 1995, with the final run made from Jalandhar to Ferozpur on 6 December.[94] The last meter-gauge and narrow-gauge steam locomotives in regular service were retired in 2000.[93] After being withdrawn from service, most steam locomotives were scrapped, though some have been preserved in various railway museums. The only steam locomotives remaining in regular service are on India's heritage lines.[92][95]
In total, there were 144 Pashi type locomotives of five distinct classes built for Sentetsu:Of these, the Pashishi class was the most numerous, and the Pashiko class was the heaviest and fastest steam locomotive ever to be operated by a Korean railway company.
Sir Herbert Nigel Gresley (19 June 1876 – 5 April 1941) was an English railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Railway (LNER). He was the designer of some of the most famous steam locomotives in Britain, including the LNER Class A1 and LNER Class A4 4-6-2 Pacific engines. An A1 Pacific, "Flying Scotsman", was the first steam locomotive officially recorded over 100 mph in passenger service, and an A4, number 4468 "Mallard", still holds the record for being the fastest steam locomotive in the world (126 mph).
Steam generators were developed when diesel locomotives started to replace steam locomotives on passenger trains. In most cases, each passenger locomotive was fitted with a steam generator and a feedwater supply tank. The steam generator used some of the locomotive's diesel fuel supply for combustion. When a steam generator-equipped locomotive was not available for a run, a so-called "heating car" fitted with one or two steam generators was inserted between the last locomotive in the consist and the rest of the train.
The Pennsylvania Railroad's class S2 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, eight driving wheels, and a six-wheel trailing truck. 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 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.
In the 1960s, construction began on new snow ploughs for the DR in East Germany as well as the conversion of steam locomotives to oil-firing. At the same time the refurbishment of diesel locomotives was taken on. The number of employees hovered around 2,000. In 1961 the former streamliner, 61 002, was converted by the factory into the high-speed, trial locomotive, 18 201, which is still operational today. This engine reached a top speed of 180 km/h and is currently the fastest, operational steam locomotive in the world. In 1981 the construction of fireless locomotives and S-Bahn bogies began, whilst the repair of steam locomotives steadily waned.
A high-pressure steam locomotive is a steam locomotive with a boiler that operates at pressures well above what would be considered normal. In the later years of steam, boiler pressures were typically . High-pressure locomotives can be considered to start at , when special construction techniques become necessary, but some had boilers that operated at over .
Maximising the efficiency of a heat engine depends fundamentally upon getting the temperature at which heat is accepted (i.e. raising steam in the boiler) as far as possible from the temperature at which it is rejected (i.e. the steam when it leaves the cylinder). This was quantified by Nicolas Léonard Sadi Carnot.
In the 20th century, Chief Mechanical Engineer of the London and North Eastern Railway (LNER) Nigel Gresley designed some of the most famous locomotives, including the Flying Scotsman, the first steam locomotive officially recorded over 100mph in passenger service, and a LNER Class A4, 4468 Mallard, which still holds the record for being the fastest steam locomotive in the world (126mph).[3]
The Heisler was the fastest of the geared steam locomotive designs, and yet was still claimed by its manufacturer to have the same low-speed hauling ability.
Alco was the second-largest steam locomotive builder in the United States (after Lima Locomotive Works), producing over 75,000 locomotives (though not all were steam, since, unlike Baldwin, Alco transitioned more readily to Diesel). Among these were a large number of well-known locomotives. Railroads that favored Alco products included the Delaware & Hudson Railway, the New York, New Haven & Hartford Railroad, the New York Central Railroad, the Union Pacific Railroad and the Milwaukee Road. Alco was known for its steam locomotives of which the 4-6-4 Hudson, 4-8-2 Mohawk and the 4-8-4 Niagara built for the New York Central and the 4-8-4 FEF and the 4-6-6-4 (Challenger) built for the Union Pacific were fine examples. Alco built many of the biggest locomotives ever constructed, including Union Pacific's "Big Boy" (4-8-8-4). Alco also built the fastest American locomotives, the Class A Atlantic and Class F7 Hudson streamliners for the Milwaukee Road's "Twin Cities Hiawatha" run. Among the ambitious state-of-the-art designs of the late steam era, Alco's Challengers, Big Boys and high speed streamliners stood out for their in-service success.
The German express locomotive, number 18 201 of the Deutsche Reichsbahn in East Germany, appeared in 1960–61 at Meiningen Steam Locomotive Works as a conversion of the Henschel-Wegmann train locomotive 61 002, the tender from 44 468 and parts of H 45 024 and Class 41. It is the fastest operational steam locomotive in the world.
Fireless steam locomotives were steam locomotives that operated from a supply of steam stored on board in a large tank resembling a conventional locomotive's boiler. This tank was filled by process steam, as is available in many sorts of large factory, such as paper mills. The locomotive's propulsion used pistons and connecting rods, as for a typical steam locomotive. These locomotives were mostly used in places where there was a risk of fire from a boiler's firebox, but were also used in factories that simply had a plentiful supply of steam to spare.
They hauled the fastest scheduled steam-powered trains in the world. Running at 100 mph or greater was required to keep these schedules; the class A locomotives were designed to cruise at over and be able to achieve . A run with a dynamometer car behind the locomotive was made on May 15, 1935 by locomotive No. 2 between Milwaukee and New Lisbon, Wisconsin. Over a stretch the speed of was recorded. This was the fastest authenticated speed reached by a steam locomotive at the time, making No. 2 the rail speed record holder for steam and the first steam locomotive to top . There are reports, without evidence or accurate records, that these locomotives could exceed . Such speeds would have placed the class A in contention with the LNER Class A4 and German BR 05 for the crown of fastest steam locomotive until that time, but no records have been unearthed. The successor Milwaukee Road class F7 was even more powerful, with a claimed top speed of .
Articulated Beyer-Garratt Cab forward Double Fairlie Duplex Electric-steam locomotive Geared steam locomotive Heilmann locomotive High-pressure steam locomotive Mallet 5AT Advanced Technology Steam Locomotive Steam dummy Steam turbine locomotive Triplex