{{Short description|Vertical plates attached to steam locomotives}} {{uncited section|date=December 2023}}
[[Image:SmokeDeflectorResearch1920.jpg |thumb|right|Photos of model locomotives without (left) and with (right) smoke deflectors in a wind tunnel of the Aerodynamics Research Institute in the 1920s]] [[Image:01118 Koenigstein.jpg|thumb|right|DRG Class 01 locomotive fitted with ''Wagner''-type smoke deflectors—the large vertical plates attached to both sides of the front (right) of the locomotive]]
[[Image:Dampflok 45.jpg|thumb|right|DRG Class 45 locomotive fitted with smaller ''Witte''-type smoke deflectors]] '''Smoke deflectors''', sometimes called "blinkers" in the UK because of their strong resemblance to the blinkers used on horses, and "elephant ears" in US railway slang, are vertical plates attached to each side of the smokebox at the front of a steam locomotive. They are designed to lift smoke away from the locomotive at speed so that the driver has better visibility. On the South Australian Railways they are called "valances".
==Overview== Smoke deflectors became increasingly common on later steam locomotives because the velocity of the smoke exiting the chimney had been reduced as a result of efficiency gains obtained by improved smokebox design, such as the Kylchap exhaust and Giesl ejector,<ref>{{cite web|url=http://www.victorianrailways.net/motive%20power/ssteam/ssteam.html|title=S class steam locomotives|accessdate=2007-03-31}}</ref> and as boilers became larger the size of the chimneys had to be reduced to maintain loading gauge.
==Styles== Various styles of smoke deflectors have been used by different railway operators. However, many are essentially a variation of one of two designs of ''Windleitbleche'' (wind deflecting plates) developed by the Deutsche Reichsbahn-Gesellschaft (the German State Railway Company) between the World Wars: the earlier, larger ''Wagner''-type deflector, and the later, smaller ''Witte''-type deflector, such as those found on the preserved LNER Gresley A3 class 4472 ''Flying Scotsman''. <ref>{{cite web|url=http://www.eurotrib.com/story/2006/1/22/151854/230|title=Monday Train Blogging: Design Dictators|publisher=European Tribune - Community, Politics & Progress|accessdate=2007-03-31}}</ref><ref name=78er.de>{{cite web|url=http://www.78er.de/BAUREIHE/baureihe.html|title=Doch was ist eine Baureihe?|accessdate=2007-03-31}}</ref>
The Southern Railway in the UK was one of the first adopters and standardised on its own distinctive style where the deflectors only reached to halfway up the smokebox from the running plate. Wind tunnel testing showed that these less tall deflectors would adequately lift the smoke on the locomotives for which they were designed, without unduly detracting from the appearance.
[[Image:SR 850 Lord Nelson.jpg|thumb|right|SR ''Lord Nelson'' class with short SR standard deflectors ]]
==References== {{Reflist}}
{{DEFAULTSORT:Smoke Deflectors}} Category:Locomotive parts Category:Steam locomotive technologies