Editing GWR 2900 Class (section)

{{Short description|Class of GWR steam locomotive manufactured 1902–1913}}
{{Use dmy dates|date=March 2020}}
{{Infobox locomotive
|name=Great Western Railway 2900 ''Saint'' class
|powertype=Steam
|image= Tilehurst with down Cheltenham express geograph-2896577-by-Ben-Brooksbank.jpg
|caption=2981 ''Ivanhoe'' at [[Tilehurst]] in 1948
|designer=[[George Jackson Churchward]]
|builder=[[Great Western Railway|GWR]] [[Swindon Works]]
|builddate=1902-1913
|totalproduction = 77
|gauge={{Track gauge|uksg|allk=on}}
|whytetype=[[4-6-0]] (thirteen examples were built as [[4-4-2 (locomotive)|4-4-2]] but rebuilt to 4-6-0 1912/13).
|uicclass=2'Ch2
|leadingdiameter={{convert|3|ft|2|in|m|3|abbr=on}}
|driverdiameter={{convert|6|ft|8+1/2|in|m|3|abbr=on}}
|trailingdiameter={{convert|4|ft|1+1/2|in|m|3|abbr=on}} (4-4-2 only)
|wheelbase=''loco:'' {{convert|27|ft|1|in|m|2|abbr=on}} – <br/>{{convert|27|ft|7|in|m|2|abbr=on}}<br/>''loco & tender:''<br/> {{convert|53|ft|4+3/4|in|m|2|abbr=on}} –<br/> {{convert|53|ft|10+3/4|in|m|2|abbr=on}}
|length={{convert|63|ft|0+1/4|in|m|2|abbr=on}}
|width={{convert|8|ft|11|in|m|3|abbr=on}}
|height={{convert|13|ft|3+1/2|in|abbr=on}}
|axleload={{convert|18|LT|t ST|lk=on}}
|cylindercount=Two, outside
|cylindersize={{convert|18|x|30|in|mm|0|abbr=on|lk=on}} or<br/> {{convert|18+1/2|x|30|in|mm|0|abbr=on|lk=on}}
|boiler=GWR Standard No. 1 (with variations)
|boilerpressure={{convert|225|psi|MPa|2|abbr=on|lk=on}} (production series)
|firearea={{convert|27.22|sqft|abbr=on}}
|fireboxarea={{convert|154.94|sqft|abbr=on}}
|tubesandflues={{convert|1485.96|sqft|abbr=on}}
|superheatertype = "Swindon No. 3" 
|superheaterarea={{convert|307.52|sqft|abbr=on}}
|tractiveeffort={{convert|20530|lbf|kN|2|abbr=on}} – {{convert|24395|lbf|kN|2|abbr=on}}
|fuelcap={{convert|5|LT|t ST|abbr=on}}
|watercap={{convert|3500|impgal|abbr=on}} – {{convert|4000|impgal|abbr=on}}
|locoweight={{convert|68.30|LT|t ST}}
|tenderweight={{convert|43.15|LT|t ST}}
|valvegear=[[Stephenson valve gear|Stephenson]]
|valvetype={{convert|10|in|mm|0}} piston valves<br/>(2935 rebuilt with poppet valves)
|operator=[[Great Western Railway]]<br/>[[British Railways]]
|operatorclass=2900 or ''Saint''
|powerclass=GWR: C<br/>BR: 4P
|fleetnumbers = 2900–2955, 2971-2990, 2998
|axleloadclass=[[Great Western Railway Weight Classification|GWR: Red]]
|numinclass=76
|retiredate=1924, 1931–1953
|disposition=One rebuilt as [[GWR 4900 Class|Hall]] class (2925/4900 ''Saint Martin''), remainder [[scrap]]ped; One 4900 example has been backdated to 29XX specification}}

The '''Great Western Railway 2900 Class''' or '''''Saint'' Class''' was built by the [[Great Western Railway]]'s [[Swindon Works]]. The class incorporated several series of 2-cylinder [[steam locomotive]]s designed by [[George Jackson Churchward]] and built between 1902 and 1913 with differences in dimensions for comparative purposes. The majority of these were built as [[4-6-0]] locomotives; but thirteen examples were built as [[4-4-2 (locomotive)|4-4-2]] locomotives and later converted to 4-6-0 during 1912/13. They proved to be a highly successful class which established the design principles for GWR 2-cylinder classes over the next fifty years, and influenced similar classes on other British railways.