To travel from NYC to Washington DC by rail - distance of about 230 miles, you pay $80 regular service or $157 for Acela Express (which is only about 15 minutes faster than the regular service).
To travel from Philadelphia to Pittsburgh - distance of about 300 miles - you pay $50.
Q: What justifies the $100+ difference in fare for roughly similar distance? A: The skin color and class of the travelers - to keep the dark skinned riff raff out of the Acela trains used mainly by corporate functionaries and politicos.
PS. I am pretty sure Jordan will come with an alternative explanation, such as the state of PA partially subsidizing travel on the Keystone line. But that only begs the question why is not the service on the NE corridor subsidized in the same way (because it is subsidized)?
Wojtek