The C.P. Huntington.

(Sacramento History Online, Public domain, via Wikimedia Commons)



Under the Whyte notation for the classification of steam locomotives, 4-2-4 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and four trailing wheels on two axles.

The configuration was only used for tank engines, which is noted by adding letter suffixes to the configuration, such as 4-2-4T for a conventional side-tank locomotive, 4-2-4ST for a saddle-tank locomotive, 4-2-4WT for a well-tank locomotive and 4-2-4RT for a rack-equipped tank locomotive.


The 4-2-4 Wheel Arrangement. Fron of locomotive on left.

(Gwernol, Public domain, via Wikimedia Commons)


The engine C. P. Huntington was one of three identical 4-2-4 tank locomotives. They were the first locomotives to be purchased by Southern Pacific Railroad in 1863, for use on light commuter services in the Sacramento area. The locomotives had serious shortcomings. The single driving axle did not carry the full weight of the engine's rear end due to the trailing truck and, in addition to being too light, it therefore lacked adhesion to reliably pull trains, especially on gradients. The short water tank on the Forney-type frame prevented the locomotives from travelling any moderate distance without consuming all of their water. As a result, these locomotives were only used when absolutely necessary.

In 1863, a sister engine, the T. D. Judah, was built by the Cooke Locomotive Works for a railroad which was unable to pay for it and was purchased by the Central Pacific Railroad. This locomotive was rebuilt to a 4-2-2 wheel arrangement in 1872.


The C.P. Huntington is dwarfed by an EMD F7 diesel-electric locomotive. Photo courtesy Southern Pacific.

(A Lyman E. Cox, Sacramento, CA, Public domain, from the W. Lenheim Collection.)



Equivalent classifications
UIC class: 2A2
French class: 212
Turkish class: 15
Swiss class: 1/5
Russian class: 2-1-2
First known tank engine version
First use: 1853
Country: United Kingdom
Locomotive: Pearson 4-2-4T
Railway: Bristol and Exeter Railway
Designer: James Pearson
Builder: Bristol and Exeter Railway


Flint and Pere Marquette Railway No. 11.

(Internet Archive Book Images, No restrictions, via Wikimedia Commons)

Private car of the Sup't, Lehigh Valley Rail-Road, ca. 1900.

(Inmates of Willard, Public domain, via Wikimedia Commons)