4-8-0

From Wikipedia, the free encyclopedia

Norfolk and Western Railway class M2 4-8-0.

Under the Whyte notation for the classification of steam locomotives, a 4-8-0 locomotive has four leading wheels arranged in a leading truck, eight coupled driving wheels and no trailing wheels. The type was nicknamed the Mastodon or Twelve-wheeler in North America. Mastodon (No. 229) was the unofficial name of the very first 4-8-0, which was built by the Central Pacific Railroad in 1882 at the Sacramento Locomotive Works.

Most 4-8-0s were built in the late 19th century or early 20th century, but the type never achieved great popularity.

The equivalent UIC classification is 2'D.

In the United Kingdom, some 4-8-0 tank locomotives were produced, including fifteen by the North Eastern Railway, designated NER Class X, later LNER Class T1.

In Austria, the wheel arrangement was used for some express locomotives: class 570 of 1915 and class 113 of 1923, both numbered as class 33 from 1938 on.

The popular C17 class locomotive used by Queensland Railways in Australia also had the 4-8-0 wheel arrangement.

In France this wheel arrangement appeared as the famous 240P. 2-4-0 referring to the number and arrangement of axles rather than wheels. The 240P was considered to be André Chapelons finest work and benefitted from his mathematical modelling to produce a highly efficient sream circuit. The locomotive was a 4 cylinder compound fitted with Lentz-Dabeg poppet valves. With a power output of 4700hp the 240P was reported to have the highest power to weigh ratio of any steam locomotive. Coupled with the elegant French style tender this was also a very aesthetic locomotive. Unfortunately none have survived into preservation.