SEPTA Regional Rail Operates 13 fully electric Regional Rail Lines, all which congregate to run through the Center City Commuter Connection Tunnel through Downtown Philadelphia. The lines can be classified as ex-Pennsylvania Railroad (arriving in Center City at 30th Street Station), and ex-Reading, arriving in Center City at Market East Station.
SEPTA Regional Rail is slowly arriving on the SubwayNut, although I still need to make probably two more trips to Philadelphia to finish it, it has a lot of stations and not that frequent service:
Chestnut Hill West Line
Paoli/Thorndale Line
Meida/Wawa Line
Airport Line
West Trenton Line
Warminster Line
Doylestown Line
Fox Chase Line
Chestnut Hill East Line
Norristown Line
SEPTA Regional Rail has the bones to be an amazing and frequent European-style regional train system. It could very easily revival the S-Bahn and RER systems, found in many major cities in Western Europe using mostly its existing infrastructure. The core reason was the decision to build and open the Center City Commuter Connection in November 1984. This tunnel combined and through-run operations through Center City Philadelphia. This project built a 1.8 mile long four track wide tunnel between the formerly competing Redding and Pennsylvania Railroads that had already electrified their suburban lines (with those few non-electrified lines all losing service around this time). This project opened a new tunnel connecting the ex-Pennsylvania Railroad’s Suburban Station with the ex-Redding Railroads lines via a new station at Market East before trains would ascend onto the Redding Viaduct. At this point in time Regional Rail lines were given R-designations pairing lines with similar ridership, from R1 through R8 (except R4) but SEPTA desiring more flexibility and not consistently interlining the same ex-Redding Line with the same ex-Pennsy Line resulted in these being dropped in 2010.
Unfortunately, SEPTA never rebuilt the rest of its stations outside of Center City on a larger scale with the high-level platforms required to allow frequent, rapid transit-like operations. This means most stations outside of Center City require passengers to get on and off trains going up and down steps with lots of stations not accessible to passengers with disabilities.
SEPTA also never reformed its work rules to allow lower-cost one person train operation (which would be impossible without rebuilding all station platforms to be high-level). Base off-peak minimum service on Regional Rail is also only every two hours (with a few exceptions with lower service at the extreme ends of the Regional Rail network). Many routes do operate every hour but only the Airport Line operates consistently every 30 minutes, 7 days a week.
Ridership went down after the Center City Commuter Connection opened. This can partially be caused changes in travel patterns caused by a 108 strike in 1983 that crippled Regional Rail operations when SEPTA took over direct operations from Conrail, along SEPTA's inexperience in running a railroad and their unique intricacies versus regular transit lines like the rest of its diverse bus, subway, streetcar, and interurban lines network. In addition, the ex-Reading Railroad viaduct was falling apart and needed to be rebuilt. This resulted in multiple months-long suspensions of service on the ex-Reading Lines primarily from April through September 1992 and May to August 1993 under the RailWorks project that were suspended outright, or passengers had to transfer to the Broad Street Subway at Fern Rock Transportation Center. SEPTA did run a few rush hour trains to and from Center City via Conrail freight tracks using diesel locomotives.
SEPTA did begin fare reform starting in the late 2010s, with turnstiles installed at Center City stations in 2018, along with readers installed for passengers to tap their Key cards on and off at all Regional Rail systems. Unfortunately, this didn't fully reform fares into a modern Proof-of-Payment system that is the most efficient way to collect fares on a Regional Rail network. Today conductors still sell tickets on board (giving passengers a SEPTA Quick Trip ticket for the faregates to exit in Center City) since Ticket Vending Machines to purchase fares weren't installed at every station and there is no penalty to boarding a train without tapping your SEPTA Key Card first, the conductor will simply “open” your trip on their hand-held device, assuming the network isn' t down (that happened a couple of times on my visit in September 2024, with the conductor irritable and making it clear that this was a frequent occurrence). If you arrive at a Center City without a ticket you can simply buy a SEPTA Quick Trip ticket from an Exit Fare Kiosk.