Monongahela Connecting Railroad

The Monongahela Connecting Railroad (reporting mark MCRR) or Mon Conn is a small industrial railroad in Pittsburgh, Pennsylvania. It was a subsidiary of the Jones & Laughlin Steel Company and a large portion of its work was for its parent company, though it also serves other industries along the line. The railroad is possibly best known for its Hot Metal Bridge, which was used to carry molten iron across the Monongahela River from J&L's Eliza Furnaces to the Bessemer converters (later, open hearth furnaces) and rolling mills at J&L's South Side facility.

The railroad was also a dieselization pioneer, buying many early diesel locomotives from Alco, General Electric and other manufacturers.

The railroad is still in existence, but in much reduced form. The Monongahela River bridge has been converted to a two-lane automobile bridge, with the adjacent hot metal bridge converted for bicycles. The bridges are collectively called the Hot Metal Bridge. The railroad serves a few small industrial customers along the north/east (right downstream) bank of the river.

Joseph L. Sorensen was Vice President of the Monongahela Connecting Railroad from 1948 until 1952.