This is believed to be the roadbed of the South and North Alabama RR at the point where the tramway would have crossed over, on its way to the Oxmoor furnace.  Research has shown that the L&N RR, which took over operation of the S&NA did a series of realignment projects to improve (eliminate) curves and in many cases to double track the busy mainline.  The Ross Bridge portion of this website shows one of these realignments.  At this location, Birmingham Rails has seen plats showing land transfers between the L&N and TCI where the old and new rights-of-way were laid out and land swapped.  At this location the L&N's main line is very close, and is also several feet higher than the old S&NA.  This roadbed likely dates from the 1860's.