A 4-4-6, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is a locomotive with: four leading wheels (at the front of the locomotive) four driving wheels (2 axles) fixed in a rigid frame, and six trailing wheels (normally mounted in a trailing truck).
Usage
United States The Providence, Warren and Bristol Railroad's No. 4 Annawamscutt was the only example of a 4-4-6 in the United States. It was rebuilt into a 0-4-4T in 1891.
France The only example of this wheel arrangement in France was the Thuile locomotive.
Other equivalent classifications are: UIC classification: 2′B3′ (also known as German classification Italian classification), and French classification: 223.
References