Pilot (locomotive)
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In railroading, the pilot is the device mounted at the front of a locomotive to deflect obstacles from the track that might otherwise derail the train. Archaically this was called a cowcatcher, and this is still the common layman's usage, but this term is deprecated and has not been used by railroad workers for more than a century.
The term "pilot", and the item itself, derive from North American usage; European locomotives tend not to have pilots, reflecting the fenced-off nature of European railway systems, although they may have life-guards — small metal bars in front of the wheels to knock away smaller obstacles.
The device itself was invented by Charles Babbage in the 19th century, during his period of working for the Liverpool and Manchester Railway.[1] However, Babbage's invention was not built, and it is uncertain whether later users were aware of Babbage's idea.
On a road locomotive, the pilot has to successfully deflect an obstacle hit at speed; the ideal is to push it upwards and sideways out of the way. The locomotive should not lift on impact or the train will follow, and the ideal is for a fairly smooth structure so that the locomotive will not get caught and pulled sideways off the track either.
The typical shape is a blunt wedge that is shallowly V-shaped in plan. In the later days of steam locomotives, the front coupler was designed to swing out of the way also, so it could not get caught up; this was called a drop coupler pilot.
Early on, pilots were normally fabricated of bars mounted on a frame; later on, sheet metal pilots were often used for their additional smoothness, and some cast steel pilots were employed for their mass and smooth shape. Early diesel locomotives followed the same plan.
Slower speed locomotives often had a pilot with steps on it to allow yard workers to ride on the locomotive; these were called footboard pilots. Footboard pilots were outlawed for safety reasons in the 1960s and were removed. Modern locomotives often have front and rear platforms with safety rails where workers can ride.
Modern diesel locomotives have flatter, less wedge shaped pilots; this is because a diesel locomotive has the cab near the front, and the crew are vulnerable to impact from obstacles pushed up by the pilot. Indeed, most are fitted with a device known as an anticlimber above the coupler to prevent struck objects from travelling up over the frame and through the cab area.
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- ^ Hyman, Anthony (1982). Charles Babbage, Pioneer of the Computer. Oxford University Press, pp.142-143. ISBN 0-19-858170-X. “Babbage suggested to Hodgson of the railway company what was later to be called a 'cow-catcher' for sweeping obstacles off the line.”
