Keystone Corridor in the context of "SEPTA"

30th Street Station, officially William H. Gray III 30th Street Station, is a major intermodal transit station in Philadelphia, Pennsylvania, United States. The station opened in 1933 as Pennsylvania Station–30th Street, replacing the 1881 Broad Street station as the Pennsylvania Railroad's main station in the city. The station is the third-busiest Amtrak station in the nation with over 4.1 million passengers as of 2023.

30th Street Station is currently metropolitan Philadelphia's main railroad station and a major stop on Amtrak's Northeast and Keystone corridors. The station is also a major commuter rail station served by all SEPTA Regional Rail lines and is the western terminus for NJ Transit's Atlantic City Line. The station is also served by several SEPTA-managed city and suburban buses and by NJ Transit, Amtrak Thruway, and various intercity operators.

The Philadelphia Main Line, known simply as the Main Line, is an informally delineated historical and social region of suburban Philadelphia, Pennsylvania. Lying along the former Pennsylvania Railroad's once prestigious Main Line, it runs northwest from Center City Philadelphia parallel to Philadelphia and Lancaster Turnpike, also known as U.S. Route 30.

The railroad first connected the Main Line towns in the 19th century. They became home to sprawling country estates belonging to Philadelphia's wealthiest families, and over the decades became a bastion of "old money". The Main Line includes some of the wealthiest communities in the country, Villanova, Radnor, Haverford, and Merion. Today, the railroad is Amtrak's Keystone Corridor, along which SEPTA's Paoli/Thorndale Line operates.

The Keystone Service is a 195 mile (314 km) regional passenger train service from Amtrak, that operates between the Harrisburg Transportation Center in Harrisburg, Pennsylvania, and 30th Street Station in Philadelphia, running along the Philadelphia to Harrisburg Main Line (known as the Keystone Corridor). Most trains then continue along the Northeast Corridor (NEC) to Penn Station in New York City.

Trips between Harrisburg and New York take approximately 3+1⁄2 hours, including 1+3⁄4 hours between Harrisburg and Philadelphia. There are also several express services that can cut the journey times of both by approximately 15 minutes.