Originally Posted by phlwookie

In reality it needs to be a game day (minute?) decision that almost completely depends on current traffic on I-76 in the area of 30th Street. It's going to be a bad rush hour due to the holiday - the question is a) is there some stupidity happening on 76 south that would slow an airport-bound taxi and b) is bad traffic overflowing onto the local streets around 30th St Station due to problems either direction on 76 or 676, and c) did most folks get out of town already because many businesses are letting out early. Most heavy traffic in that area due to the holiday will be heading to the Walt Whitman (76) or Ben Franklin (676) bridges over the Delaware River then onto the Jersey Shore.

Given that the airport trains leave 30th at :04 and :34 past each hour, OP potentially needs to wait nearly 30 min for the airport train based upon an Amtrak arrival at 4:34. Without traffic, a taxi would get you to PHL A-East or West in about 15-20 min but will be 5-6 times more expensive than the train ($28.50 set base fare from Center City to the airport + ~$1.10 fuel surcharge + tip). SEPTA will cost $6.50 per person one way if bought in the station before boarding, or $8.00 each (cash only) if bought on board. SEPTA trains and ticketing are located up a ramp in the NW corner of the (beautiful) main hall of 30th Street; taxi stands are located on the 29th Street side (Center City-facing, east side).

If getting to Philly earlier isn't an option, here's what I'd do. When leaving Wilmington on Amtrak (assuming coming from the south, else a few minutes out of Trenton), pull up Google Maps and turn on the traffic layer. If either the local roads immediately around 30th Street Station (2955 Market St, Philadelphia, PA) or the route from there along I-76 east to 26th St to PA 291 to the airport - the usual taxi route - are gummed up, plan on the train. A taxi may offer to take I-676 east to I-95 south to the airport if 76 is backed up, but unless there's a serious problem on 76, this is a much longer route, and not traffic risk free, especially on 676 in Center City and I would not suggest that.

Were it risk-averse me and I couldn't get to Philly earlier, I would default to the taxi option first if traffic isn't a big issue as it should buy some more time at the airport, knowing the airport will busy as well with the holiday and you need to still have passports/visas checked before boarding even with online check in, though this can be done at either the Club or the gate. However, probably 40-50% of the time, traffic in the area of the station and on 76 east until 26th St will be an issue.

Unless Amtrak is >20 min late you should make the SEPTA connection easily, but there is no margin for error thereafter. Should you miss the 5:04 SEPTA train to the airport, the only way you make the flight is with a skillful, fast taxi driver and a large tip if there's traffic. The 5:04 SEPTA actually arrives A-East at 5:19, though, not 5:24, so there's 5 more minutes to play with.

Originally Posted by phlwookie

I think you'll make it. It probably won't be stress free. And have a plan B; US 728 to LHR (9:50pm) still has lots of seats open, for instance.