I think that we all agree, in our own separate but reasonable ways, that this was a mistake. The argument seems to be in the realm of how big a mistake, and where to place blame.
Personally, if I were King of the Rail Roads, I would have foreseen this possibility and put into place some sort of communication and cooperation policy and procedure. Assuming that this was not an extremely rare occurrence, why did the two railroads not have a better way to handle this type of movement? How about an extra signal or two, or some sort of mutually-agreed upon radio protocols? How about just plain having a 3-hour course, out in the field, with the parties involved, (management, senior motormen, and dispatcher/radio operator) and go through the motions in a real-life test of the movement? Why wasn't the SEPTA dispatcher notified by the AMTRAK dispatcher that this was occurring? Certainly they must have access to SOME shared telecom or radio channels? Didn't some RR emergency managers foresee that there should be a process for just this type of situation? Lots of questions, so easy to ask from the Monday-morning QB's easy chair.