4-6-0

A 4-6-0 steam locomotive, under the Whyte notation for the classification of steam locomotives by wheel arrangement, has four leading wheels on two axles in a leading bogie and six powered and coupled driving wheels on three axles with the absence of trailing wheels.

In the mid-19th century, this wheel arrangement became the second-most-popular configuration for new steam locomotives in the United States, where this type is commonly referred to as a Ten-wheeler. As locomotives pulling trains of lightweight all-wood passenger cars from the 1890 to the 1920s, they were exceptionally stable at near 100 mph (160 km/h) speeds on the New York Central's New York-to-Chicago Water Level Route and on the Reading Railroad's line from Camden to Atlantic City, New Jersey.

Overview

Tender locomotives

During the second half of the nineteenth and first half of the twentieth centuries, the 4-6-0 was constructed in large numbers for passenger and mixed traffic service. A natural extension of the 4-4-0 American wheel arrangement, the four-wheel leading bogie gave good stability at speed and allowed a longer boiler to be supported, while the lack of trailing wheels gave a high adhesive weight.

The primary limitation of the type was the small size of the firebox, which limited power output. In passenger service, it was eventually superseded by the 4-6-2 Pacific type whose trailing truck allowed it to carry a greatly enlarged firebox. Prussia and Saxony however went directly to the 2-8-2 Mikado type (pr. P10(39) / sax. XX HV(19) class); Karl Gölsdorf reversed the 2′C1 Pacific type to the 2-6-4 Adriatic type to accommodate an even larger firebox and better curve performance (type 310).