Photo taken by J.P. in June 2013
BH Photo #255824
It looks like there were at least 2 spans of a truss bridge here in the 1952 and 1962 images from historicaerials.com. I think from the images there is at least 1 pier to the NE that never got a span (maybe more, the images aren't great). They may have wanted to connect Jersey Avenue in the Southwest to the other side of the creek but never finished the project.
I think you're probably right about it not being completed if it doesn't show up on the topographic map, Clark. With how sudden World War 2 production stopped in the INAAP it wouldn't surprise me that the bridge was just never completed. They never used IOW Plant 2 after the Second World War, like they did other with other parts of INAAP, so they would have no reason to have a bridge over there.
From walking the approach to the bridge back up to the gravel road in Charlestown State Park it looks as though they had at least completed the necessary road cuts. Looking at the current satellite photos it appears similar work was done on the other side as well, and the road does lead to where the old plant buildings used to be on the other side. https://maps.google.com/maps?q=38.457445,-85.615427&hl=en&ll...
The 1937 Charlestown quad shows none of the military roads or rails. The 1950 topo shows a grade that appears to line up more with the military road than the rail. Had it been completed it probably still would show, even if abandoned, five years after the war.
The link should lead to the 1950 map. The 1948 Owen quad to the east shows no sign of any road continuing to the east other than the one still there. No buildings suggesting military activity until the 1961 Owen quad, and no rail line or bridge showing.
Unless it was a really ephemeral thing my guess is "never built".
Are you sure it was never completed? IOW Plant 2 (the rocket propellent plant) was over on the other side of Fourteen Mile Creek. I always assumed the bridge was built for the plant, and was removed after production stopped there at the end of World War 2 or when the land was donated for the creation of Charlestown State Park.
There appears to be remnants of another corridor down through there. I wonder if it's not from a former rail line as it seems a bit close to the old highway bridge, and with it being concrete we know it's pretty much post 1900 circa.
Found this incomplete bridge in the middle of the woods in charlestown state forestry down creek from the abandoned pony truss. Anyone happens to know anything please leave a comment.