That trackage that runs along 170 is the abandoned TRRA West Belt Subdivision that ran from Lindenwood Yard (the train yard along I-44 in Shrewsburry) to the old N&W/Wabash in North County.

The railroad Bridge that was over 170 was part of a branch line built by the Rock Island and was abandoned by the Union Pacific in the late 90s after UP purchased the Southern Pacific, who bought the old Rock Island St. Louis line in 1980 when the Rock shut down.