I was informed of an existing link between 30th Street's lower level and the former Reading lines by a member who goes by the handle of "Gruntled", on this thread over on the NJT forum. It was described thus:
Gruntled wrote:Diesels can go from 30th street—lower level. Then at North Philly, hang a left via the 16th Street connector to the former Reading lines. On to Wayne Jct., etc.Does this connection still exist, and if so, what condition is it in? Basically, could trains run on it tomorrow, if need be (to exaggerate slightly)...? And of course, the bigger question is why it wasn't used to retain SEPTA diesel service of the past.