1904 Train Depot - Kingsville Texas

Identifying Steam Locomotives

As the steam locomotives were developed a system of identification was needed.  Each manufacturer designed and produced their own locomotives of different weights and formats.  The common factor seemed to be the arrangement of the wheels.  Frederick Methvan Whyte developed a system to classify and identify locomotives by their wheel arrangement in 1900.  The first number indicated the number of leading wheels, under the “cow catcher”.  The second number (in the case of articulated locomotives the second and third number) identified the number of drive wheels.  The last number was the number of trailing wheels.

The wheels had to be arranged in certain ways to properly distribute the weight of the locomotive so as to minimize damage to the track.  The front wheels gave the locomotive stability and supported the smoke box and cylinders at the front of the locomotive.  The drive wheels are generally larger than the leading and trailing wheels.  They support and distribute the main weight of the locomotive as well as propel the locomotive.  The trailing wheels support the boilers, fire box, and cab of the locomotive. 

The first three locomotives purchased for the passenger trains of the St. Louis, Brownsville & Mexico line were Baldwin 440’s.  This wheel alignment was sometimes called “American”.  By 1949 the Kingsville Division of Missouri Pacific still sported 20 Mikados (282), 20 Consolidations (280), 15 Ten-Wheelers (460), and 3 Pacifics (462).  The Kingsville Record of November 4, 1953, reported that all Gulf Coast Lines locomotives (the Kingsville Division included) would be totally dieselized by the coming year.

Frederick Whyte was a mechanical engineer who worked for numerous railroads including the New York Central railroad.  He also worked with the Australian railroad with regard to uniform railway gauge.  He is most well known for his system of locomotive classification.  This list of Whyte’s System of Locomotive Classification is from “Steam and the Chattering Brass” by Norman Resor. 

Whyte’s System of Locomotive

Classification

(about 1900)