Monongahela Connecting Railroad
（重定向自MCRR）
The Monongahela Connecting Railroad (reporting markMCRR) or Mon Conn was 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 served 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.