The Classification Of Steam Locomotives

February 17, 2020

Today we often refer to trucks as “eighteen-wheelers,” a quick means of identifying certain long-distance haulers. So it was with steam engines at the turn of the 20th century.


In 1900, Frederick Methvan Whyte, of Dutch descent, who worked for the New York Central Railroad, devised a notation for steam engines to quickly denote their type and general usage.

The Whyte system counted the total number of small wheels forward of the main drive wheels (leaders), the number of main drive wheels (drivers) and the number of small wheels behind the main drive wheels (trailers), each number separated by a hyphen. These smaller, unpowered wheels (leaders & trailers) helped keep the engine on the track on curves especially over long distances and at higher speeds. They were largely unnecessary for smaller, slower, workhorse type engines.

Thus a locomotive with four leaders, six drivers and two trailers was referred to as a 4-6-2. There were many configurations manufactured. A representative illustration below pictures a 4-4-0 (the wheels on the tender or coal car are not counted).

Articulated engines were basically two engines coupled together and sharing a common boiler. They were denoted by three numbers, a plus sign, and three more numbers. Thus an articulated engine might be designated a 4-6-2+2-6-4. These were much larger engines designed for very heavy-duty hauling.

Other systems of classifying engines existed, but the Whyte system was by far the most popular. Diesel engines, which came later, did not use the Whyte system.

The two last steam engines to run on the Morehead & North Fork railroad were number 12 and number 14 (the numbers represented the sequence in which the engines were acquired by the company). Both were 0-6-0s, smaller “switch” engines, often used in rail yards for moving rolling stock from one position in the rail yard to another. Both engines were used on the M&NF for the short distance, low-speed hauling required to carry logs and clay.