This historic tunnel was built when the Frisco built their own line into Saint Louis, but was inevitably abandoned when the Frisco created a bypass in 1929.
The tunnel is a short structure, only 475 feet total. It contains brick and stone features. These include a brick lining inside the tunnel. The exterior has been constructed of stone.
Presently, the tunnel is a deteriorated condition, although a nature trail which leads to the east portal is open. These portals have been sealed off with gates and brick.
Fortunately, the tunnel has been at least partially preserved. It is a landmark in the City of Kirkwood.
The author ranks this bridge as moderately significant, because it is a good example of a well preserved historic structure.
The photo above is an overview. The author hopes to get more photos soon.