Editing LMS Coronation Class (section)

== 1948 locomotive exchange trials ==
In May 1948 the BR Executive arranged a [[1948 Locomotive Exchange Trials|series of locomotive exchanges]] whereby each of the "Big Four" previously independent companies would submit its various locomotives for evaluation. It was intended that each locomotive would be tested not only on its own home territory, but on the tracks of its three other "rivals". The aim was to ascertain the best qualities of the competing locomotives in order to help design future locomotives.{{r|Nock84|p=173}} In that dynamometer cars were to accompany the test trains, whilst coal consumption was to be accurately measured,{{r|Baker|p=125}} it was unclear whether the aim was to test the locomotives for power or for efficiency – the two are somewhat incompatible.

[[File:Paddington 3 railway station geograph-2192807-by-Ben-Brooksbank.jpg|thumb|No. 46236 ''City of Bradford'' at Paddington on the WR during the 1948 locomotive exchange trials.]]

The locomotive classes were all pre-chosen by BR, but the various regions were free to choose, within certain parameters, which specific locomotives were to be represented. Tasked with supplying a suitable Coronation, the London Midland Region (LMR) selected No. 46236 ''City of Bradford''.{{r|Nock84|p=173}} Regions were also free to choose their drivers. To drive the engine throughout, the LMR chose driver Byford from Camden shed who was seen to be sufficiently experienced.{{r|Baker|pp=75 and 125}} ''City of Bradford'' was then tested on its home ground between London Euston and Carlisle, on the [[Eastern Region of British Railways|Eastern Region (ER)]] between [[East Coast Main Line|London Kings Cross and Leeds]], on the [[Western Region of British Railways|Western Region (WR)]] between [[Great Western Main Line|London Paddington and Plymouth]], then finally on the [[Southern Region of British Railways|Southern Region (SR)]] between [[West of England Main Line|London Waterloo and Exeter]].<ref>{{cite book |last=Bradley |first=Rodger P. |title=The Standard Locomotives of British Railways |year=1984 |location=Newton Abbott |publisher=[[David & Charles]] |isbn=0-7153-8384-1 |page=14}}</ref>

The results showed that, compared with its peer locomotives, ''City of Bradford's'' coal consumption was the second lowest (and well below the third lowest), but its power output was well below any of its peers.{{r|Nock84|pp=176–179}} In later years some insight has emerged concerning No. 46236's outings. On the WR, having arrived at Plymouth from Paddington, the dynamometer crew were amazed that such a large locomotive had consumed so little coal;<ref>{{cite book |last=Dunn |first=J.M. |title=Reflections on a Railway Career LNWR to BR |year=1966 |publisher=Ian Allan |location=London}}</ref> on the undulating tracks of the SR west of Salisbury, it was alleged that coal consumption was held down by running gently uphill then racing downhill without any attempt to follow the timetable passing times.<ref>{{cite magazine |last=Riemsdijk |first=J.T. van |title=LMS, T.F. Coleman and locomotives |magazine=Backtrack |date=Feb 1997 |volume=11 |location=Penryn |publisher=Atlantic Transport Publishers |editor-last=Blakemore  |editor-first=Michael |issn=0955-5382 |pages=106–107}}</ref> Additionally, a photograph of the locomotive leaving Kings Cross, bound for Leeds on the ER, shows the locomotive with so little coal on board that none could be seen even from a somewhat elevated vantage point. {{r|Baker|p=125}} In other publications, driver Byford has been heavily criticised for his lacklustre driving.<ref>{{cite book |last=Cox |first=E.S. |title=British Railways Standard Steam Locomotives |edition=2nd |year=1973 |orig-year=1966 |location=London |publisher=Ian Allan |isbn=0-7110-0449-8 |chapter=2}}</ref>{{r|Nock84|p=176}} Certainly, Byford was so obsessed with minimising coal consumption that he never attempted to demonstrate any other facet of performance, but when coal consumption was being so accurately measured it was a reasonable assumption to draw that coal efficiency was the predominant requirement. Many years later, there was a degree of exoneration for driver Byford when the whole procedure was described as "the most inconsequential and unrepresentative series of competitive trials ever to be held on the railways of Great Britain".{{r|Nock84|p=173}}