Fastest Steam Train In The World – London And North Eastern Railway Class A4 Pacific

On Sunday, September 11th, 2011, in Engineering, Railroading, Steam Locomotives, by Al Gengler
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The fastest steam train in the world, the LNER Class A4 4468 Mallard 4-6-2 Pacific was developed by Sir Herbert Neigel Gresley.

Sir Herbert Nigel Gresley

Sir Herbert Nigel Gresley was one of Great Britain’s most famous steam locomotive design engineers. His invention of a three-cylinder design with only two sets of Walschaerts valve gear, the Gresley conjugated valve gear, produced a smooth running engine with more power at a lower cost than a more conventional three sets of Walschaerts gear. Gresley served his apprenticeship at the Crewe works of the London and North Western Railway, afterwards becoming a pupil under John Aspinall (engineer) at Horwich of the Lancashire and Yorkshire Railway. He was made Outdoor Assistant in the Carriage and Wagon Department in 1901; in 1902 he was appointed Assistant Works Manager at Newton Heath depot, and Works Manager the following year. In 1904 he became Assistant Superintendent of the Carriage and Wagon Department of the L&YR. A year later he moved to the Great Northern Railway (Great Britain) as Carriage and Wagon Superintendent. Gresley was appointed chief Mechanical engineer of the newly-formed London and North Eastern Railway, and in 1936 he was awarded a knighthood by King Edward VIII and an honorary Doctor of Science by Manchester University.

His Class A3, the Flying Scotsman, was the first steam locomotive to officially record a land speed of over 100mph while in passenger service.

Gresley’s wedge-shaped streamlining of the LNER Class A4 4-6-2 Pacific engine was inspired by a Bugatti designed prototype rail car developed for the French railroad which he had observed on a trip in the early thirties. Gresley added a tight fit tender to the A4 locomotive to enhance the aerodynamics along with a matching set of six coaches.

Gresley’s LNER A4 express locomotive design was refined with the assistance of Cambridge University Professor William Dalby (engineer). Using the wind tunnel facilities at the British National Physical Laboratory (United Kingdom) at Teddington, the high-speed aerodynamic engine wind-tunnel-tested out at speeds of over 100 miles per hour.

The new LNER Class A4 4-6-2 Pacific, Mallard, was 70 feet long and weighed in at 165 tons, including the tender.

LNER Class A4 4468 Mallard 4-6-2

It was the ideal candidate for a record railroad speed run on a set course. Built in February of 1938 with a dual chimney and Kylchap blast pipe to further improve the engine’s performance the Mallard, in garter blue livery, was only five months out of the engine works when it was chosen to make a run at the world record. A long straight right-of-way with a slight downhill gradient, at Stone Blank south of Grantham, was selected as the marked performance raceway. Previously a German record attempt had built up speed on a downhill slope before the race distance started, but Stoke Bank in England did not have that luxury. The run up to the starting line was very short on almost level ground

Selected to crew the locomotive on its record attempt were driver, Joseph Duddington, an experienced  railroading engineer renowned for taking calculated risks and fireman, Thomas Bray.

Thomas Bray, Joseph Duddington with rail inspector Jenkins after their record setting run.

Pulling six coaches and a dynamometer car the Mallard began the run just after 1:00 PM. The clocked speed run, well-documented, was fast enough to set a land speed record for rail vehicles. Unfortunately the Mallard sustained minor damage to its end bearing during the run and had to limp back to its Peterborough base. But on that day the Mallard became one of the legends of the road. The results of that run were now a matter of record. On July 3, 1938 the LNER Class A4 4469 Mallard 4-6-2 Pacific became the fastest steam engine in the world reaching a speed of 126 mph.

After its successful record run, the 4468 Mallard remained in service until 1963 when the it was retired. From July of 1938 to October 1963 the A4 4468 Mallard 4-6-2 logged almost one and a half milllion main line passenger miles.

The Gresley designed LNER A4, 4468 Mallard 4-6-2 Pacific , still holds the record for being the fastest steam locomotive in the world: 126mph over a marked course.

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One Response to Fastest Steam Train In The World – London And North Eastern Railway Class A4 Pacific

  1. Austin Smith says:

    I was doing a report on this locomotive. Never knew it had minor diamage to it when it came back from its run.

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