Smoke deflectors, sometimes called "blinkers" in the UK because of their strong resemblance to the blinkers used on horses, are vertical plates attached to the front of a steam locomotive on each side of the smokebox. They are designed to lift smoke away from the locomotive at speed so that the driver has better visibility.
Smoke deflectors became increasingly common on later steam locomotive designs as efficiency gains through improved smokebox design and reduced back pressure on the cylinders in turn reduced the uplift of smoke exiting the chimney.
There have been various styles of smoke deflectors used by different railway operators worldwide. However, many are essentially a variation of one of two designs of Windleitbleche (smoke deflector) originating from the Deutsche Reichsbahn-Gesellschaft (German national railways between the World Wars): the earlier, larger Wagner type deflector, and the later, smaller Witte type deflector.