SEPTA still owns the entire Octoraro Branch from Wawa to the Maryland Line,
Yes they do
Or if that one doesn't work, just click on "railroad map" (and the type 10 county maps are rather nice as well):
On the railroad map, be sure to check out how many green lines bear "[SEPTA]" on them, that is a line owned by SEPTA, but operated by a shortline freight hauler. In the case of the Octorara Branch it appears to be a subsidiary of the Morristown and Erie.
In my humble opinion, an electrification, double tracking and rebuilding of the Octorara branch out to Kennet Square or, even better Oxford, would make more sense than reinstating service to West Chester. Since the West Chester line turns north for it's terminal, you end up with the R3 terminating close to the R5. This is not a terrible thing, but ideally I'd like to see SEPTA's regional rail system fan out to cover all directions (except from the east, for now) with equal aplomb given poltical restrictions. Straight west of SEPTA is amply covered by the R5 Thorndale, to the north is handled by the various Reading routes, the northwest area is handled by R6 and hopefully SVM, and the southern approach is inadaquately covered by the R2. In this system a R3 that runs straight west from Wawa could do demonstrable good at clearing off the congested roads in the area. Cross County commuters could be catered to with a more direct connection between the Rt101 and the R3 at media, or the Rt102 at Clifton-Alden.
Just about the only problem I could see would be that the Media line isn't exactly set up to handle rush hour expresses to Kennett Square, Wawa, or Media (depending on the length of the line) that the line would require to snatch drivers off the road. It could be argued that the R5 Thorndale express trains have it best, with a low-congestion 4 track line and all. Perhaps running Kennett Square service similar to the West Trenton service would be the best idea after all.