The
Union Railroad was a switching and transfer line owned by
U.S. Steel, serving a number of plants in the area and connecting with six trunk line railroads. Operation was only at low speed, thus a leading truck's stability was not required. The intent was to eliminate
helper requirements on grades, and thus a locomotive larger than the Union's previous
switchers and
2-8-0 "Consolidations" was needed. Ten driving wheels allowed the application of sufficient
tractive effort within the
axle load limits of the line, and the requirement for a large
firebox and plentiful steam-raising ability necessitated the trailing truck. To increase tractive effort still further, a
booster engine was fitted to the leading
tender truck. The unusual wheel arrangement was also a result of the turntable restrictions on the total wheel base.[2]
The
Union Railroad was a switching and transfer line owned by
U.S. Steel, serving a number of plants in the area and connecting with six trunk line railroads. Operation was only at low speed, thus a leading truck's stability was not required. The intent was to eliminate
helper requirements on grades, and thus a locomotive larger than the Union's previous
switchers and
2-8-0 "Consolidations" was needed. Ten driving wheels allowed the application of sufficient
tractive effort within the
axle load limits of the line, and the requirement for a large
firebox and plentiful steam-raising ability necessitated the trailing truck. To increase tractive effort still further, a
booster engine was fitted to the leading
tender truck. The unusual wheel arrangement was also a result of the turntable restrictions on the total wheel base.[2]