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Mallard - Record-holding Steam Locomotive

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In the 1930s, the British railway companies were facing increased competition from road and air travel. It was clear that services between the major cities had to be faster, more reliable, and more comfortable.

A New Breed of Locomotive

Sir Nigel Gresley, the Chief Mechanical Engineer of the LNER1, was well aware of this. His impressive A3 locomotives were fast and efficient, and they did the job, but in light of the heightened competition he began researching streamlining to see whether it would be feasible to produce improved versions of his A3s to compete with other streamlined trains, such as the German State Railways diesel-electric Fliegende Hamburger and the US Burlington Zephyr, both of which were attracting publicity for their high speed services.

After a series of trials on his current A1 and A3 designs, during which A1 Flying Scotsman broke 100mph and A3 Papyrus is said to have reached 108 mph, the LNER board commissioned Gresley to use his new streamlining ideas to design a train for the proposed Silver Jubilee service to Newcastle.

What Gresley eventually came up with, after long periods of wind tunnel testing and internal reworkings, was the all new class A4. However, the majority of public opinion was that these were merely A3s fitted with streamlined casing2. Some thought the LNER was bowing to the latest craze, and some even went as far as to say that it was not true streamlining and that the design team did not know what they were doing!

However, it was not only cosmetic changes that were made. Along with the distinctive new shape Gresley had made some improvements under the bonnet. All of the steam passages were streamlined, along with the boiler pressure being increased from 220psi to 250psi. Also, the cylinders were decreased slightly in size so that the valve diameters could be increased to nine inches. These changes produced free steaming within the restrictions of the three cylinder design, which is also seen on the A3s, and further modifications were made at latter dates, including the additions of a Kylchap double-blastpipe exhaust and Westinghouse QSA brake valves.

Whatever the thoughts of the doubters though, they were silenced after witnessing the demonstration run from Kings Cross to Grantham on 27 September, 1935, where the train touched 112.5mph. In fact, because of the smoothness of the footplate, the locomotive's crew only thought they were travelling at 90 mph, and it wasn't until Gresley squeezed though the corridor tender to inform them that some of the passengers were becoming nervous that they slowed down!

The first official service was on the 1 October, 1935, hauled by No. 2509 Silver Link, and a further three locomotives were built for the 'Silver Jubilee' service to Newcastle. This service was a great success, cutting the travel time between Kings Cross and Newcastle down to an amazing four hours. This success led to an extension of the service to Edinburgh, and the building of a further five A4s. By 1937, a third service to Leeds and Bradford had commenced, giving birth to Britain's first inter-city network of super-fast train services.

Competitive Instincts

Gresley's new A4s paved the way for streamlining in Britain, and it wasn't long before others followed suit. The LMS produced their streamlined 'Coronations' and even the Southern railway had a crack with their 'Battle of Britain' class.

Friendly competition ensued between the rival companies, particularly the LMS and LNER. Higher and higher speeds were being reached by the drivers despite often direct breaches of safety regulations, but eventually, after stern warnings from railway directors, the heads of both companies struck a gentlemen's agreement that they would no longer put speed before passenger comfort and safety.

When this agreement was reached it was one of the LMS Coronations that held the record at 114 mph, but Gresley, being the competitive type, was not about to let that stand.

Record Attempt

Gresley was determined to attain the high speed record with one of his designs, and it was under the cover of regulation brake tests that he had his chance, partly because of the lack of passengers on board and partly because of the recording equipment in the dynamometer car that would be able to authenticate a record should one be achieved.

The locomotive chosen was A4 4468 Mallard3 and its driver was to be a Mr Duddington, of Doncaster. The test train, made up of the dynamometer car and six other vehicles, weighed 240 tons. On 3 July, 1938, the train started to the north of Grantham and headed south along the LNER route.

As it passed the station it was travelling at a modest 24 mph and after two and a half miles, at a slight upwards incline4, the train had accelerated to 59.75 mph. One and a half miles later the speed had increased to 69 mph and up the final one and a half miles of incline, through the tunnel to Stoke box5, it reached 74.5 mph as the summit box was passed.

From that point there was no more upwards incline so the way was clear for Mallard and her crew to go for the record. From milepost 100 the speed was 87.5 mph; at milepost 93 it was 119mph; around milepost 90 125 mph had been reached; and the dynamometer record, for a very short distance, even revealed the tremendous maximum of 126 mph! At this point the six foot eight inch driving wheels were doing more than 500 revolutions a minute! That's over eight revolutions a second!

This though was not just an opportune burst of speed. For the five miles between mileposts 94 and 89 the average speed was 120.4 mph, and for a continuous three mile stretch, from milepost 92 to milepost 89, the speed actually exceeded 120 mph!

After this display there was no doubt; Mallard's speed had exceeded that not only of the LMS Coronation, but of all other steam locomotives in the world whose high speed performances were properly authenticated and recorded, and because of modern speed limitations on steam traction it is very unlikely that this record will ever be broken.

After the run a commemorative plate was affixed to Mallard's footplate, and it is still there today. It reads:

3rd JULY 1938
OF 126

After the record-breaking run, Mallard overheated and had to limp back to Doncaster for repairs. It turned out that the inside cylinder of the A4 was under greater strain at high speeds than the two external cylinders. This overloading was mostly responsible for the failure. After the repairs though, Mallard remained in service until 1963, when it was withdrawn and preserved after a lifetime distance of almost 1.5 million miles.


Today, Mallard is part of the National Collection on display at the National Railway Museum in York, and is one of six surviving A4s6, including Sir Nigel Gresley, the locomotive affectionately named after its designer. Although Sir Nigel Gresley is still in working order, Mallard, because of the expense of keeping her in running condition and the popularity of her as an exhibit at York, is currently on static display and is likely to remain so for the foreseeable future.

1London & North Eastern Railway.2The technical classifications of the A4s are similar to those of the A3, which can be found in the Flying Scotsman entry.3Gresley thought of the name Mallard while he was feeding ducks at Salisbury Hall.4An incline of 1 in 200.5Still at the same incline.6Though only Mallard still wears the full streamlined casing the A4s wore in their heyday. The others have had the covering removed from the wheels to ease maintenance, (this is shown in the Sir Nigel Gresley link.)

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