The station you seen is a replica that was built by an electrical contractor, I do not know if they are still in business. This was the former PY&A of the PRR. AFAIK, no railroad structures exist in Warren anymore [not counting bridges]. The PY&A was being run by Ohio Central from Niles to N.Warren the they had rights on former E-L [Erie Second Sub, the original A&GW] from there to Latimer [NS Youngstown line, originally NYC/LS&MS]. That traffic disappeared with closing and total destruction of the former Republic Works. I have not been in area for awhile, so I do not know if coke works still are active or have been shutdown [its traffic was being serviced by CSX at one time].
I think Ohio Central still comes up PY&A onto the Erie line to serve some plants between Mahoning Ave and Elm Road. That line was the original line [remember A&GW was Salamanca to Dayton]; it is out of service from Mahoning Ave [RT45] to Leavittsburg, that is where you saw track/r.o.w. under Rt.82. Leavittsburg was the junction/crossing of the Erie's First Sub Mahoning Div [Cleveland-Warren-Youngstown-Sharon-Pymatuning Jct/Transfer] with the Second Sub [Pymatuning Jct-Latimer-Cortland-northside Warren-Ravenna-Kent]. If it is still there, single track south of those lines in a parallel curve was the B&O's line from Newton Falls-Warren-DeForest, which was its original Pittsburgh-Akron main.
The Ohio Star Forge AFAIK does not use rail service though money was expended to rebuild the former B&O from NWarren to the former Copperweld facility.
The PY&A from northside of Warren to Ashtabula is now a bike/hike trail. Interestingly, the former Erie Lisbon branch from Niles south is part of the trail system; it actually was part of the PY&A but was sold to the Erie so they could build from Niles to Youngstown to New Castle.
I have to go now, most likely others can give more updated information.