Union Electric Co. No. 4 is an 0-4-0F steam locomotive it was built in 1946 by H. K. Porter in Pittsburgh, PA, for the Union Electric power plant in Venice, IL. where it used to work as a switcher.
It switched at the plant until 1976 when it was retired and put in storage until 1980, when it was sold to the Transport Museum Association of Brooklyn, IL.
In 1982, it was donated to the Illinois Railway Museum where it is today placed on public display.