Pittsburgh is Famous for Bridge to Nowhere but did you know there is also a Railroad Tunnel to nowhere as well?

When I was a kid the Fort Duquesne Bridge sat for many years uncompleted on Pittsburgh North Side one confused motorist actually tried to cross it and lived to tell when his car almost fell into the river.   But
as you crossover the West End Bridge  from the North Side to West end if you look over to the far right on West Carson Street and look up you will see an abandoned Tunnel of some type that is blocked off about 3/4 of the way up and just top 1/4 of the arch is visible .
No one seems to know its actual origins .
Some say it was the start of the proposed Pittsburgh to Stubenville Ohio Railroad  which sounds possible.
as many railroads where started and then never completed as well  as nothing more than on paper.
There also seems to be no where where it may have come out of the hill as well, just an entrance.
way too big to be used by a brewery  to store barrels of beer which there where many such tunnels in city at one time it was definitely built for a train or trolley.

Tunnel entrance mostly blocked off and chocked with weeds.

At one time where the Pat Bus Way comes off onto Carson I remember before they built it there was once a ramp for what looked like trains to come on to W. Carson and  was designed to feed into the tunnel.
Of course this is not the only mystery construction along W. Carson  There was an aqueduct built under W. Carson raising it several feet where trains pass over W.Carson from Brunot Island  which Penn Dot is now remodeling and lowering road to original level during a multi million dollar revamp of the road.
Even a gentleman who has an extensive web site with tunnels and bridges is unsure what the tunnel  and aqueduct was built for as well . Someday some where in some engineers office some one may come across the original plans and solve the mystery but for now both are unsolved.