Geared steam locomotive
A geared steam locomotive is a type of steam locomotive which uses gearing, usually reduction gearing, in the drivetrain, as opposed to the common directly driven design.
Egide Walschaerts
Whilst at Mechelen in 1844 he developed a new type of valve gear (a mechanism that allows for adjustment of the travel of the valves that distribute the steam to the cylinders and enables a steam locomotive to be put into reverse and to economise steam). He was not permitted by the company to patent the device himself as he was deemed of too lowly a rank. An engineer colleague and friend, M. Fisher, applied for the patent on his behalf but never claimed any contribution to it. Walschaerts name on the documents erroneously omitted the final 's' causing confusion over its correct spelling over the succeeding years. A locomotive built at the Tubize workshops fitted with the Walschaerts valve gear was awarded a gold medal at the 1873 Universal Exhibition in Vienna. This valve gear came to be used in the majority of steam locomotives, and became almost universal throughout the 20th Century.