Washington Union Terminal (MP 136.0) comprises twenty stub-end upper level tracks, with two side and nine double-sided high-level platforms with umbrella sheds, in its high-level station on the west side, facing north, and two island plus two side low-level through platforms with umbrella sheds, serving six tracks, on the east side, immediately north of the Capitol Hill Tunnel, plus some extra platform/track space on the east side without tunnel access. The station concourse is at the high level, south of the stub end of the platforms and extending east over the low-level tracks, with the magnificently restored depot area to the south of the concourse. All of the platforms are electrified with overhead AC catenary, with just enough extending south of the low-level platforms to permit locomotive changeovers. (The catenary used to extend south to Potomac Yard, in PRR days and until Conrail ceased electric freight operations in the 1980s.). There is a road bridge overhead near the north end of the platforms.
The line north from the high-level stub end platforms and the low-level platforms, which come together in the north station throat at the crossovers at K Tower (MP 135.9), with the Metro Red Line alongside to the west and two signal bridges north of the tower, splits at the crossovers at C Interlocking (New York Avenue, MP 135.0), where the Red Line's New York Avenue station is on the west side, and bridges over New York Avenue with another street bridging overhead (where a second road bridge is under construction in April, 2012), and the non-electrified CSX line continuing north and the electrified Northeast Corridor turning east-northeast to CP Avenue (MP 134.6), where the north leg of the wye from the ex-B&O line from Cumberland trails in.
As far as Alexandria, the former Southern route to Atlanta is shared with the CSX (RF&P) Route to Richmond and the Deep South. As far as Manassas, the former Southern route is shared with Virginia Rail Express, an operator of commuter trains to Washington DC, whose trains also run south on the RF&P to Fredericksburg. For passenger trains, the route starts in the low-level (through platforms) section of Washington Union Station. Immediately to the south of the platforms, at A Interlocking (MP 136.0), the double track line plunges into a tunnel under Capitol Hill, and emerges among the federal office buildings to the south. As it passes among these buildings on the south side of the National Mall, bridging over I-95 below, the CSX (ex-B&O) and NS (ex-Conrail, ex-PRR) freight lines join from the east at Virginia Avenue Junction (CP Virginia, MP 137.1). Amtrak owns the line as far as Virginia Avenue Junction.