Conversation so far:
where does the allegheny river start and end
The Allegheny rises in north central Pennsylvania, in central Potter County and joins with the Monongahela River at The Point in Downtown Pittsburgh, Pennsylvania to form the Ohio River
how long is the allegheny river
The Allegheny river is approximately 325 miles long
where does the name allegheny river come from
The name of the river, Allegheny, comes from one of a number of Delaware Indian phrases which are homophones of the English name, with varying translations.
when did the allegheny river tunnel go into service
The Allegheny River Tunnel went into service in 2012.

Question: what is the tunner used for
Self-contained rewrite: what is the allegheny river tunnel used for