Well I'm not sure just what Amtrak plans to do, but either one train will always be late on it's entire run, they are going to change the schedule for one of the trains, or they are going to combine the two trains.
You are right B51 Amtrak does have some trains that leave Penn at the same time or at least within a minute of one another. That works in Penn with 21 tracks to choose from.
However in this case Amtrak must choose one of the above options, since both 155 and the Cardinal are carded to stop at Newark, Trenton, Philly, Wilmington, and Baltimore at the same time. That is impossible, unless they are combing the trains into one consist.