Smoke deflectors, sometimes called "blinkers" in the UK because of their strong resemblance to the blinkers used on horses, and "

elephant Elephants are the largest living land animals. Three living species are currently recognised: the African bush elephant ('' Loxodonta africana''), the African forest elephant (''L. cyclotis''), and the Asian elephant ('' Elephas maximus ...

ears" in US railway

slang A slang is a vocabulary (words, phrases, and linguistic usages) of an informal register, common in everyday conversation but avoided in formal writing and speech. It also often refers to the language exclusively used by the members of pa ...

, are vertical plates attached to each side of the

smokebox A smokebox is one of the major basic parts of a steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is ...

at the front of a

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

. They are designed to lift

smoke Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwante ...

away from the locomotive at speed so that the driver has better visibility. On the

South Australian Railways South Australian Railways (SAR) was the organisation through which the Government of South Australia built and operated railways in South Australia from 1854 until March 1978, when its non-urban railways were incorporated into Australian Natio ...

they are called "valances".

Overview

Smoke deflectors became increasingly common on later steam locomotives because the velocity of the smoke exiting the

chimney A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typical ...

had been reduced as a result of efficiency gains obtained by improved smokebox design, such as the Kylchap exhaust and

Giesl ejector A Giesl ejector is a suction draught system for steam locomotives that works on the same principle as a Injector, feedwater injector. This ejector (German: , or ) was invented in 1951 by the Austria, Austrian engineer, Dr. Adolph Giesl-Giesling ...

, and as boilers became larger the size of the chimneys had to be reduced to maintain

loading gauge A loading gauge is a diagram or physical structure that defines the maximum height and width dimensions in railway vehicles and their loads. Their purpose is to ensure that rail vehicles can pass safely through tunnels and under bridges, and k ...

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 ''Deutsche Reichsbahn'' (), also known as the German National Railway, the German State Railway, German Reich Railway, and the German Imperial Railway, was the German national railway system created after the end of World War I from the re ...

(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''. 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.

References

{{DEFAULTSORT:Smoke Deflectors Locomotive parts Steam locomotive technologies