Looking west
Photo taken by Patrick Feller
License: Creative Commons Attribution (CC BY)
BH Photo #289204
There remains compelling evidence for a railroad origin for the bridge supports still visible. Among that evidence:
http://books.google.com/books?id=6H47AAAAIAAJ&pg=PA389&lpg=P...
While the structure of the riveted piers might support the argument for a bridge preceding the FM road, concrete rubble near the southwest bank supports the argument for a road.
It wouldn't be the first time that a bridge (or at least its substructure) had served two purposes over time.
Unfortunately I've yet to find an image of the bridge, but https://www.newspapers.com/newspage/10460384/ shows that the bridge was closed due to a failing pier.
HistoricAerials has amazing aerial views of the long-lost truss.