Cross-Appalachian passenger service will never be really competitive with driving unless they can consistently run at an average speed of at least 50 mph end-to-end. The Pennsylvanian does the 353 miles between Philadelphia and Pittsburgh in 7.3 hours for an average speed of about 48 mph. That's almost good enough, but, of course, we know that the train doesn't always run on schedule.
However, the highway distance between the two cities is only 305 miles, so a car traveling at an average speed of 50 mph will be able to do the trip in 6 hours. Thus, for the train to be competitive, they'll either have to speed up the train or cut out some curves and shorten the distance of the rail route. Hopefully, this could be done without having the expense of something like a base tunnel.
Of course, even with the slower speed, the current Pennsylvanian is still competitive for people traveling to the smaller intermediate towns, most of which are not near the Turnpike and don't have alternative bus service. (Hi there, Huntingdon!) But if you really want the train to be a significant player in the transportation mode-share in this corridor (and take cars of the road), it will need to be sped up, and, of course, have more frequent trains.