page_title: LNER Class A4
section_title: Performance in service
hierarchical_section_title: LNER Class A4 / Performance in service
caption_attribution_description: English: George Haygreen (left) on his retirement day with Charlie Fisher
context_page_description: The Class A4 is a class of streamlined 4-6-2 steam locomotive designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognisable, and one of the class, 4468 Mallard, holds the world record as the fastest steam locomotive. Thirty-five of the class were built to haul express passenger trains on the East Coast Main Line route from London Kings Cross via York to Newcastle, and later via Newcastle to Edinburgh, Scotland. They remained in service on the East Coast Main Line until the early 1960s when they were replaced by Deltic diesel locomotives. Several A4s saw out their remaining days until 1966 in Scotland, particularly on the Aberdeen – Glasgow express trains, for which they were used to improve the timing from 3.5 to 3 hours.
context_section_description: No other British steam locomotives have a longer or more consistent record of high speed running than the A4s. Instances of 100 mph running by them must exceed those of all other types combined, though 90 mph running was a relatively rare event with steam traction, much less 100 mph. It should also be remembered that A4s operated on the East Coast Main Line which has more opportunities for high speed running (particularly Stoke Bank) than any other in the UK.
  In August 1936 the Silver Jubilee train on the descent of Stoke Bank headed by 2512 Silver Fox driven by George Henry Haygreen achieved a maximum of 113 mph (181.9 km/h), then the highest speed attained in Britain with an ordinary passenger train. 
  The fastest recorded post-war speed with British steam was also recorded by an A4. This occurred on 23 May 1959 on the Stephenson Locomotive Society Golden Jubilee special when 60007 Sir Nigel Gresley achieved 112 mph when hauling 400 tons down Stoke Bank. The driver, Bill Hoole, had hoped for an attempt to beat Mallard's record but Alan Pegler, who was on the footplate and mindful of the risks, told him to ease off.
  Although A4s were primarily designed for high speed express work they were also capable of high power outputs. In 1940, 4901 Capercaillie exerted 2200 drawbar horsepower on the straight and level track north of York when hauling 21 coaches (730 tons gross) at an average of 75.9 mph for 25 miles. On W.A. Tuplin's method for grading steam locomotive performance based on both power output and duration of effort, this was the highest value ever achieved by any British locomotive, at Grade 26.
  The highest recorded power output from an A4 was 2450 drawbar horsepower when Mallard herself was hauling 11 coaches (390 tons tare, 415 tons gross) up Stoke Bank at a sustained 80 mph in 1963. O.S. Nock thought this performance superior to Mallard's world record run in 1938. An A4 with the same load on a "good run" would be doing about 50 to 60 mph at the summit of Stoke Bank. On a run on 8 September 1961 Mallard had its train travelling at 78 mph.
  To put all this in perspective the highest possible drawbar horsepower from a Class 40 diesel (a class which was supposed to replace the A4s,) was 1450, though they could achieve this figure over long distances and with no effort from the crew.
caption: George Henry Haygreen (left) on his retirement day with Fireman Charlie Fisher
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