From memory, I know I will miss something.
At the base of the hill, used to be the r.o.w. of the Erie [E-L] Mahoning Div, 1st Subdiv., torn up years ago, overpasses filled in, and grade crossings now gone. Believe that track still exists from just west of MLK [W. Federal Street]; that is Ohio Central now. The Museum of Industry sits on r.o.w. and the Youngstown station was in the ground floor of the Commerce Bldg.
Along the Mahoning River on the east bank was the PRR E&A line [now NS]. The former PRR and Greyhound station still exists on MLK [Federal St], and was last I knew a fireworks store. Greyhound moved over to the transit bus center about 1991.
The B&O [now CSX] as you mentioned is just across the river with its station building, part of which still used by Amtrak's Three Rivers, and I am correct that a new restaurant has opened?
The arches to west of there was the Lake Erie & Eastern, a subsidiary of P&LE that was used as a freight bypass line by NYC to Girard from Struthers. Also some hot metal runs were run from Campbell to the bRier Hill works of YS&T. Most of r.o.w. was detsroyed in 1998-2000 by city getting rid of the arch structures over streets.
We had discussions of these lines in the previous forum. I did not mention the Canal Branch that was in the vicinity of former PRR line along river; just can't remember what tracks still exist or easily seen.