Union Pacific #4420
The UP 4420 is a 0-6-0 class engine, referring to the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles and no trailing wheels. This class of engine is unstable at high speeds but good for pulling fairly heavy loads at lower speeds. Many 0-6-0 class engines were made for military use in Europe.
Including Lima Locomotive, three different companies manufactured 0-6-0 class engines. Of the hundreds made, we can find only one that has been restored, the UP 4466, restored as a coal fired engine. It is on static display in Sacramento.