At Harrisburg (MP 104.6), where the station has two high-level brick island platforms serving four electrified tracks, with a peaked overall roof, footbridge connecting platforms, and depot on the southwest side of the line. East of Harrisburg, the line is electrified with overhead AC catenary as the Keystone line of the former PRR (and its stations have high-level platforms, like the NorthEast Corridor), but Amtrak's long distance trains keep their diesel traction into Philadelphia, where reversal is required anyway.
The line east heads southeast, double track, 15 mph, beneath a road bridge overhead at the east end of the station, through the interlocking and crossovers at State (MP 104.6), where the speed limit rises to 50-45/40 and then to 90/70-45/40, passes beneath the former Reading line coming across the Susquehanna River, and runs along the east bank of that river, past a road bridge overhead, a highway bridge overhead, MP 104, and a road bridge overhead, with Bethlehem Steel's Steelton Plant with eight or so tracks on the northeast side of the line for several miles and tracks from that plant trailing in at its east end, past a road bridge overhead, the passenger station with two short side platforms, each with a shelter, at Middletown (MP 94.7), where a former Reading branch trails in from the north, to the crossovers at CP Roy (Royalton, MP 94.3), where the former PRR Royalton Branch along the east bank of the river departs to the northeast side of the track, curves southeast to pass beneath the main line, and heads south, past Three Mile Island, while the main line turns south-southeast.