I am not sure, but isn't it the case that if you have an Amtrak ticket ex-30th St. or arriving there, you can use that ticket or stub to travel SPETA to any City Zone station by Regional Rail? I seem to recall that I was allowed to use an Amtrak ticket to go to University City from 30th St. But I must admit I have never read the exact wording of the rule.
I initially thought you were right, but upon further investigation, the SEPTA Regional Rail Division Tarriff limits the honoring of Amtrak tickets or stubs to 30th Street, Suburban, and Market East. From the tarriff:
CROSS-HONORING OF AMTRAK TICKETS:
AMTRAK tickets are not accepted on SEPTA trains, except between Thirtieth Street and Market East Station. Passengers displaying a valid AMTRAK ticket will be carried between Thirtieth Street and Market East (and intermediate points) at no additional charge. This privilege is extended only when there exists a signed, written agreement between SEPTA and AMTRAK regarding this cross-honoring. AMTRAK tickets cannot otherwise be accepted for transportation on SEPTA Regional Rail Division service.
Yes, the University City and Temple University stops, while
technically "Zone C" (Center City), really aren't equivalent to the three "real" Center City stations in all ways.
For instance, you need a ticket to get to them.
It's not just that your Amtrak ticket will let you get between any two of 30th, Suburban, and Market East: in practice, your grocery receipt could do it too. Basically, 1/3 of the train's passengers get off -- and all of those seats refill with new riders -- at each of 30th, Suburban, and Market East. Adding to the chaos, Suburban Station is the crew change point on all Regional Rail trains, so on inbound trains from the west final ticket inspection is before 30th St; after the crew change at Suburban, first ticket inspection isn't until after Market East. For inbound trains from the east, it's just the reverse. There are never ticket inspections between 30th St and Market East, because of the huge change-over in passengers at each of these stops (4 minutes apart) coupled with the crew change in the middle. The new crews would never know which of the passengers the old crew had visited if any effort to do ticket collection took place immediately before crew change.
Basically, allowing Amtrak tickets for downtown traffic is a great courtesy, but it isn't costing SEPTA anything because they're already yielding those short-distance rides for free due to the nature of the "run-through" system where, for a few stops, a trainset is basically two trains (ie, one coming in from the west and ending in Center City, whose last three stops are 30th, Suburban, and Market East; and one starting in Center City and heading east, whose first three stops are 30th, Suburban, and Market East; or else the other way around).