you can check the train status online for the past few days and the Pennsylvanian was anywhere between 25 minutes early to 120 minutes late.
So, like airlines it is really luck of the draw. If you take the train I would recomend upgrading to business class, the upgrade is only $20 each way.

The Pennsylvanian had a car that is 1/2 business class and 1/2 cafe car. The business class seats are 2-1 (coach is 2-2). They have a ton of leg room the seats lean back pritty far, have foot rests, and you get free non-alcoholic drinks from the cafe car. The cabin is small (only 1/2 a car) and is almost always free of small children so you should have no problem getting work done.