LNER Class A4 4468 “Mallard”

LNER Class A4 4468 “Mallard” is recognized for its record setting run on 3 July 1938, when it reached 126 mph, a record for speed utilizing steam traction. The record was set on Stoke Bank near Grantham on the East Coast Main Line.

In the 1930s, the Gresley A4 4-6-2 Pacific locomotives were the pinnacle of speed. Their streamlined casing gave the illusion of speed, even when standing still. On 3 March 1938, Mallard emerged from the storied Doncaster works, painted in garter blue, with its striking streamlined appearance. Designed by famed locomotive designer, Sir Nigel Gresley, Mallard was one of thirty five A4 locomotives designed by Gresley for the LNER. Mallard, along with its A4 counterparts, were designed as express locomotives to haul the railway’s premier trains, such as the Silver Jubilee. 

The Class A4 was a both a revolutionary and striking locomotive, as it included a fully streamlined exterior, enlarged firebox, and increased boiler pressure to permit high speed running. These significant advantages quickly earned the class the distinction of hauling the railway’s most prestigious trains, including the famous Flying Scotsman. The streamlining and speed of the A4 reduced the trip between London King’s Cross to Edinburgh Waverly by a half hour, thereby, relegating many A3’s to secondary service.

Syd Young Photo

The Class A4 came to fruition when Sir Nigel Gresley rode Germany’s “Flying Hamburger” in 1933. Gresley was impressed, and realized the aerodynamics and speed could be achieved on a steam locomotive with ample streamlining equipment. Furthermore, Gresley determined he could achieve these results utilizing his current A3 locomotive. The A3 was rigorously tested, and the locomotive was deemed a sufficient base. Class A3 Papyrus achieved a top speed of 108 mph, which was close to the top speed of the Flying Hamburger, however, the A3 had a full rake of coaches behind it.

The streamlined design of the locomotive catered to the comforts of the crew as well, as the streamlining and Kylchap boiler deflected the smoke over the cab, and out of the crew’s line of vision. Interestingly, the streamlining on the A4 class was derived from the Bugatti Rail Car, which Gresley had studied while visiting France. According to the LNER Encyclopedia, throughout the design process, Gresley was assisted by Prof. Dalby at the National Physical Laboratory at Teddington, in which rigorous tests were performed on the best tactic to deflect smoke away from the cab, for better crew visibility.

Upon delivery, Mallard wore the trademark garter blue, red wheels, and silver outside castings. Although Mallard may have looked similar compared to its counterparts, it was distinctive, as it was the first A4 that included a Kylchap Blastpipe, which proved the deciding factor for utilizing the locomotive for the record breaking run. This type of blast pipe proved advantageous, as it improved draughting and enhanced disposition of exhaust, especially operating at higher speeds.

Hugh Llewelyn photo

These increased speeds warranted increased braking power, as the railway was currently utilizing the vacuum brake, instead of the air brake, already utilized by fellow trunk line competitor, LMS. Gresley decided that the Westinghouse air brake system was sufficient, and invited representatives from Westinghouse to perform brake tests with the railway. Once the Westinghouse crew arrived, they were told by LNER staff that they would attempt to break the speed record, in an attempt to keep the LMS unaware of the run. Furthermore, according to LNER Encyclopedia, the LNER civil engineering department most likely would not allow this degree of speed, as the track speed during the time was only 90 mph.

With its streamlined design, increased boiler pressure, and enlarged firebox, LNER decided to test the top speed the locomotive could operate. Mallard, along with a Dynamometer car to assist recording speed, and to monitor track conditions, and seven coaches set out for their record breaking run. Interestingly, Mallard’s driver during the run, Joseph Duddington was known to take risks. Duddington was joined by fireman Thomas Bray, and inspector J. Jenkins. Prior to the Mallard shattering the world record for steam traction, the German DRG Class 05 previously held the title, clocking in at 124.5 mph.

At age 61, Duddington drove Mallard into the history books, recording a top speed of 126 mph on the slightly, downhill Stoke Bank, south of Grantham. Once again referencing LNER Encyclopedia, Mallard performed routine brake tests on the down journey, and the Westinghouse team was offered alternative transportation if they preferred not to be on board during the record breaking run. However, the Westinghouse team decided to witness history, and remained on Mallard. As the train began its up journey, it passed Grantham station at 24 mph, Stoke signal box at 74.5 mph, 116 mph at milepost 94, 120 mph at milepost 92.75 and 89.75, and 125 mph for a mere 306 yards. The record had been broken!

Hugh LLewelyn

One flaw of the A4 class was an overheating bearing inside the cylinders called the “little big end”, thus, the class was equipped with a “stink bomb” that would explode upon overheating the warm the crew. Unfortunately, once Mallard hit its record breaking speed, the middle big end began to overheat, leading the crew to slow the train to 90 mph, until reaching Peterborough, where an Ivatt Atlantic took the train the remainder of the journey. Mallard was repaired, and returned to revenue service less than a week later.

During wartime in the forties, Mallard and its A4 siblings had their side skirting removed for ease of maintenance and was repainted in wartime black. Neither Mallard or other members of the class were restored with their side skirts after the war, however, for preservation purposes, Mallard’s side skirts were restored in 1963.

Upon entering retirement, the locomotive failed to turn a wheel under its own power until the 1980s, when it was restored to operational condition. While in operable condition, the locomotive hauled various excursions throughout 1986-87. However, this would be the only time thus far, that Mallard has operated in preservation.

In 2013, in honor of the 75th anniversary of the Mallard’s record breaking run, UK Class A4 residents, Mallard, Bittern, Sir Nigel Gresley and Union of South Africa, were once again joined with its counterparts exported after retirement in the United States and Canada. Dominion of Canada, and Dwight D. Eisenhower were shipped from their respective countries to the UK in 2013, where they attended the celebration at the National Railway Museum. While in the UK, Dominion of Canada, and Dwight D. Eisenhower received cosmetic work such as paint and other touch ups.


Today, Mallard can be admired for generations to come, as it currently resides in the National Railway Museum’s Great Hall, and is one of the museum most popular attractions. The Mallard, along with its Class A4 counterparts, revitalized Britain’s railway’s during the genesis of the automobile and airline transportation, which were severely cutting into the railway’s ridership. The sheer style and class of Gresley’s locomotives were a welcome sight to both railway enthusiasts, and casual onlookers alike, and with the help of the NRM’s preservation efforts, will continue for countless generations.


Throughout its career, Mallard could be seen along the BR Eastern Region in a variety of liveries and tenders. Furthermore, the locomotive received twelve boilers throughout its life in revenue service. Paint schemes and road numbers worn by Mallard include its original garter blue appearance (#4468), wartime black (NE), post war garter blue(22), BR Blue (60022)and BR green(60022) until retirement in 1963, when it was repainted into its original garter blue appearance after entering preservation.

The locomotive was paired with seven different tenders of two varieties throughout its lifetime. One tender was the standard tender delivered with the locomotive in 1938, which it retained until the beginning of British Rail in 1948. Post 1948, the locomotive received a corridor tender. The corridor tender, introduced by Gresley in 1938, gave the crews the ability to change shifts on the fly, by passing through a walkway in the tender to the locomotive. Oftentimes, the relief crew would be situated in the first car of the train.

Date Built1938
DesignerSir Nigel Gresley
Whyte Classification4-6-2 Pacific
Length7 ft 3/8 in (21.650m)
Width9 ft (2.743)
Height13 ft 1 in (3.988m)
Weight102 long tons
Fuel TypeCoal
Fuel CapacityCoal: 8 long tons
Water Capacity5,000 imp gals
Boiler Pressure250 psi
Cylinder Size18.5 in x 26 in (470mm x 660mm)
Brake TypeVacuum
Max SpeedRevenue Service: 90 mph

Max: Mallard record 126.4 mph

Tractive Effort35,455 lbf
Preservation StatusNational Railway Museum

Color: garter blue

Status: Static display

Tender Numbers

3 March 1938-14 March 19395639
5 May 1939 – 16 January 19485323
5 March 1948 – 12 March 19535648
12 March 1953- 21 July 19585330
27 August 1958 – 30 May 19625651
30 May 1962 – 25 April 19635670
25 April 1963 – Present5642



Lifelong Rail Enthusiast and Owner of Worldwide Rails

Recent Posts