Editing LMS Coronation Class (section)

== Records ==
[[File:Coronation scot BNF.jpg|thumb|left|No. 6220 ''Coronation'' on its record breaking journey on 29 June 1937.]]

=== British speed record ===
Between 1937 and 1939, two significant records were set by locomotives of the Coronation class. Before the introduction of the ''Coronation Scot'' service, No. 6220 ''Coronation'' headed a special train of invited guests from [[Euston railway station|London Euston]] to [[Crewe railway station|Crewe]] on 29 June 1937. After a fast but uneventful run the engine was accelerated up to high speed. Just south of Crewe, the train (disputably)<ref>{{cite book |last=Nock |first=O.S. |author-link=O. S. Nock |year=1971 |title=Speed Records on British Railways |publisher=[[David & Charles]] |location=Newton Abbot |isbn=0-7153-5342-X |pages=163–164}}</ref> achieved a speed of {{convert|114|mph|km/h}}, narrowly beating the previous British record for a steam locomotive (held by the [[London and North Eastern Railway]] (LNER)). The brakes were applied far too late at such a speed and the result was that the train entered a series of crossover points at Crewe much too fast. Fortunately, Stanier had designed an inherently stable locomotive and both ''Coronation'' and its following train held the rails, although most of the crockery in the dining car was smashed, much to the consternation of the assembled guests{{r|Nock84|pp=82–83}}{{r|Roden|pp=26–31}} In contrast to the LNER's record-breaking effort the previous year, when [[LNER Class A4|A4 Class]] No. 2512 had suffered severe damage when the centre cylinder's big end bearing failed,<ref>{{cite book |last=Tuplin |first=W.A. |title=British Steam since 1900 |publisher=Pan Books |location=London |year=1969 |isbn=0-330-02721-2 |url-access=registration |url=https://archive.org/details/britishsteamsinc00pan |page=130-131}}</ref> No.6220 was undamaged and was driven back to London the same day at an average speed of {{convert|79.9|mph|km/h}}, maintaining over 100&nbsp;mph for several miles.<ref name="Hollingsworth">{{cite book| last=Hollingsworth| first=Brian| title=The illustrated Encyclopaedia of the World's Steam Passenger Locomotives| publisher=Salamander Books| location=London| year=1982| isbn=0-86101-106-6 |page=152}}</ref> The LNER was to regain its ascendancy on 3 July 1938 when A4 Class No. 4468, ''Mallard'' regained the British and world records with a recorded maximum speed of {{convert|126|mph|km/h}}.{{r|Nock84|p=86}}

=== British power record ===
Following an earlier test using No. 6234 ''Duchess of Abercorn'' which indicated that the locomotive's power was compromised by its single blastpipe, a double blastpipe and chimney were installed.{{r|Roden|pp=38–42}} On 26 February 1939, a retest was undertaken and No. 6234 hauled a train of 20 coaches, including a dynamometer car, from Crewe to Glasgow and back. Even though the load was {{convert|610|LT|ST t|abbr=on}}, the train was hauled up the climbs to the summits at [[Shap Summit|Shap]] and [[Beattock Summit|Beattock]] at unprecedented speeds. Drawbar horsepower, representing the power conveyed directly to the 20 coach train, was frequently over {{convert|2000|hp|kW|abbr=on}} and a maximum of {{convert|2511|hp|kW|abbr=on}} was recorded. This remains the official British record for a steam locomotive to this day.{{r|Roden|pp=42–46}}{{r|Nock84|pp=86–87}} Because there were unmeasured variables, the horsepower at the cylinders could only be estimated; [[Cecil J. Allen]] thought it to be {{convert|3333|hp|kW|abbr=on}} whilst [[O. S. Nock]] was more conservative at {{convert|3209|hp|kW|abbr=on}}.{{r|Roden|p=46}}{{r|Nock84|p=87}} This sustained power output could not be expected on day-to-day service as it was beyond the shovelling capacity of a single fireman, and two firemen were carried for this test run.<ref name="Hollingsworth"/>

Some seventeen years later, No. 46225 ''Duchess of Gloucester'', a virtually identical sister engine, was tested by British Railways on the open road on the Settle and Carlisle line.{{r|Nock84|pp=224–239}} Again it was established that a continuous drawbar horsepower of {{convert|2000|hp|kW|abbr=on}} was readily sustainable. Strangely, the drawbar power output on the stationary test plant at Rugby could only be coaxed up to an absolute maximum of {{convert|1710|hp|kW|abbr=on}} which in retrospect casts doubt on the validity of the methodology.{{r|Nock84|p=229}}