Whyte notation
The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte, and came into use in the early twentieth century following a December 1900 editorial in "American Engineer and Railroad Journal". The notation counts the number of leading wheels, then the number of driving wheels, and finally the number of trailing wheels, groups of numbers being separated by dashes. Other classification schemes, like UIC classification and the French, Turkish and Swiss systems for steam locomotives, count axles rather than wheels.
Frederick Methvan Whyte
Education: Franklin Academy, 1889.
Entered railway service May 1, 1889, since when he was consecutively to January 1, 1890, draftsman, Motive Power Department, Lake Shore and Michigan Southern Railway; January 1, 1889, to February 1, 1892, Testing Department and Drawing Room, Baltimore and Ohio Railroad at Baltimore, Maryland; February 1, 1892, to June 1892, special testing work, Mexican Central Railroad, Mexico City; June 1892, to December 1894, general railroad engineering in Chicago, chiefly with Chicago and South Side Rapid Transit Railroad and in railway newspaper work; July 1895, to September 1896, draftsman, Northwestern Elevated Railroad, Chicago; July 1, 1897, consulting engineer, Chicago; July 1, 1897, to August 10, 1899, mechanical engineer, Chicago and North Western Railway and secretary, Western Railway Club; August 15, 1899, to November 1, 1904, mechanical engineer, New York Central and Hudson River Railroad; November 1, 1904, to 1910, general mechanical engineer, same road; Lake Shore and Michigan Southern, Boston and Albany Railroad, Lake Erie and Western Railroad, and Indiana, Illinois and Iowa Railroad; September 15, 1905, to 1910, also general mechanical engineer Rutland Railroad; November 1, 1911, to 1913, vice-president, Hutchins Car Roofing.