Editing BR standard classes (section)

== Background ==

[[Robert Riddles]] put his case for continuing to build steam locomotives in his presidential address to the Institution of Locomotive Engineers in November 1950.<ref>{{cite web |last1=Riddles |first1=R. A. |title=Nationalisation and the Mechanical Engineer |url=https://journals.sagepub.com/doi/abs/10.1243/jile_proc_1950_040_061_02 |website=Journal of the Institution of Locomotive Engineers |pages=675–694 |language=EN |doi=10.1243/JILE_PROC_1950_040_061_02 |date=1 November 1950}}</ref> He compared capital costs to show that steam was cheaper than the alternatives, though he did not mention productivity differences, except to say fuel costs did not rank very high relative to total costs. For example, a [[BR standard class 5|Class 5]] cost £16,000, compared to £78,100 for a [[British Rail Class D16/1|1,600 h. p. diesel]], £138,700 for a [[British Rail 18000|gas turbine]], or £37,400 for [[British Rail Class 77|electric]]. He calculated the costs per [[Horsepower#Drawbar power|drawbar horse power]] as £13 6s (steam), £65 (diesel), £69 7s (turbine) and £17 13s (electric).<ref>{{cite magazine |magazine=The Railway Magazine |date=January 1951 |pages=60–61 |title=Standardisation and Comparative Costs of Motive Power on B.R.}}</ref> Riddles retired in 1953.

=== Design ===
From 1951, BR started to build steam locomotives to its own standard designs, which were largely based on LMS practice but incorporating ideas and modifications from the other constituent companies, continental Europe and North America. Their design was overseen by Riddles.

Characteristic features were [[taper boiler]]s, high running plates, two cylinders and streamlined cabs.