Neither of these is Acela Express. The 9:00am is train #155 which is a "regional service" train from NYP to Phila. It begins at NYP and ends at 30th St Station. It has a cheaper fare than the train I want.
The train I want is the 11am train #643 which is a "Keystone" from NYP to Harrisburg. Since they are both unreserved, am I ok to get a ticket for the former with the promo code and use it on the latter?