At Valley Junction (MP 178.9), in Cumberland, with a street alongside to the north, the former B&O "West End" line trails in from the southwest at a double junction with crossovers, with a wide road bridge overhead. The double track line turns south, with speed limit 20 mph on track 1 and 25 mph on track 2, crossing Baltimore Avenue and Williams Street at grade (15 mph across the crossings), with a Holiday Inn on the west side of the line, to the passenger station in Cumberland (MP 178.3), with platform and depot on the east side of the line, where the speed limit rises to 40-35, passes beneath a wide road bridge at the station, past MP 178 and another highway overbridge beyond (that becomes the street alongside to the east), and turns southeast, with a divided street alongside to the east, at the Virginia Avenue signal bridge and crossovers (MP 177.0), where a spur heads southwest to the former WM line, to pass the CSX Locomotive Shops and Cumberland Yard on the southwest side of the line, with speed limits 60-50 or 55-50, and the divided street still alongside to the east, a bridge over a stream, more signals and crossovers at West Hump (MP 175.7), and turns south, with speed limit 50-45 from MP 174.6 to 174.4 and 60-50 thereafter, past a bridge over a stream, with a divided street still alongside to the east, to the end of the yard with signals and crossovers at Mexico (MP 173.4).
From Cumberland to Washington, DC, the line traverses the Potomac River valley, first coming alongside the river at the cantilever signal bridge at North Branch (MP 172.6), where a connector from the former WM trails in from the northwest (the bridge carrying the former the WM right-of-way, which has disappeared east of this point, is still there) and a road bridge overhead, crossing the river to its south bank in West Virginia, passing a brief 50 mph passenger speed between MP 171.3 and 171.2, and turning east-southeast, with speed limit 30 mph, at the cantilever signal bridge (Intermediate Signals) at Patterson Creek (MP 170.6), where there was once a cutoff line on the west side from the "West End" line at McKenzie, speed limit 60-50 again from MP 170.2, another cantilever signal bridge (intermediate Signals) at Dan's Run, 65-50 from MP 167.7, a cantilever signal bridge (intermediate Signals) at Keen's Curve, a dirt track grade crossing, and two extra tracks on the north side with a maintenance yard beyond them.
The line turns east at the signals at Green Spring (MP 164.2), where there are crossovers, a 21,450 ft. siding for eastbound trains on the south side of the line (with a scale for weighing coal trains) and a shorter siding on the north side, and the former B&O South Branch Valley Railroad trails in from the south-southwest. The line turns briefly northeast and then southeast, with speed limit 40-35 on the curve, past detectors at MP 162.4, a bridge over the South Branch, French, east, with passenger speeds of 60, 55, and 60 again, past Intermediate Signals at Long's Crossing, the B&O-style signals and crossovers at Okonoko (MP 158.1), a bridge over a stream, and Intermediate Signals (signal bridge) at Little Cacapon, east-northeast, past an extra track heading off on the north side (the remains of the original line east of here) and two road bridges overhead, and Intermediate Signals at Paw Paw (MP 148.3), through Carruthers Tunnel (speed limit 40 mph), past Intermediate Signals at Carruthers, and then north along the Magnolia Cutoff line that replaced the earlier line following the West Virginia side of the river to Doe Gully.
The Magnolia Cutoff starts by running on a high wall, with speed limit 50-45, behind and above the route of the earlier line at a lower level, and then proceeds north, with speed limit 55-50, through a number of tunnels in an area of densely wooded hills with different trees lining the river, crossing the river a couple of times (into Maryland and back again), specifically across Kesler Bridge (which also crosses the path of the old line), through Graham Tunnel (in MD), across Magnolia Bridge (which also crosses the path of the old line), past Intermediate Signals at Magnolia, through Stuart Tunnel, jogging east past Intermediate Signals (B&O-style signals on a signal bridge) at Hansrote (MP 143.6), north again past a dirt track grade crossing and through Randolph Tunnel, jogging east again to resume the original route at the Intermediate Signals at Doe Gully, north, with speed limit 50-45 past detectors at MP 140.7
The river closes on the west side, then angles away again, past a dirt track grade crossing, a signal bridge with B&O-style signals at the crossovers at Orleans Road (MP 139.4), east-southeast along the riverbank again, with speed limit 40 mph between MP 136.5 and 136.0, past a dirt track grade crossing, and Intermediate Signals at Turkey Foot, to Intermediate Signals at Great Cacapon, and north-northeast with speed 50-45 to MP 134.8, 65-50 to MP 131.5, 55-45 to MP 130.7, 60-50 to MP 129.2, 65-50 to MP 127.5, 40 mph to MP 126.1, 65-50 to MP 125.0, 50-45 to MP 124.5, and 60-50 thereafter, past Intermediate Signals at Silent Hill, a bridge over a side river, Intermediate Signals at Grasshopper Hollow, a hiking trail in the woods between the line and the river, with a big display marker facing the river at one point, and Intermediate Signals at St. John's Run to the signal bridges with the B&O-style (Color Positio Light) signals (replaced in 9/07 by signals remotely controlled by the Dispatcher) and crossovers at HO Tower (MP 123.1), where the tower itself closed on 9-17-07, there is extra track on the north side and the Berkeley Springs Industrial Track trails in from the south, and Hancock (MP 122.9), where there is a yard on the north side, a road bridge overhead, a signal bridge with B&O-style signals, more yard tracks on the north side, and a signal bridge with triple-head signals.
The line turns southeast past Intermediate Signals at MP 120.5, two dirt track grade crossings, MP 119, a dirt track grade crossing, Intermediate Signals at MP 118.8, a dirt track grade crossing, a dirt road grade crossing, detectors at MP 117.4, Sleepy Creek (MP 117.3), Intermediate Signals at MP 116.3 (Tyer Creek), a 60 mph sign, a 50 mph sign, crossovers at Miller (MP 114.4), where the speed limit is 50 mph between sections at 65-50, a long siding on the north side starts, and a signal bridge at Cherry Run, where a connection off that siding heads across the river to the former WM line that starts again from this point and the long siding diverges from the routing of the main line, which turns east, and then abruptly south (with speed limit 45-40), away from the river, past a bridge over a side river, Intermediate Signals at MP 111.x (Borch YArd), MP 110, a grade crossing, two rocky cuttings, Intermediate Signals at MP 108.0, North Mountain (MP 107.5), where the speed limit is 65-50, a grade crossing, MP 107, a grade crossing, a bridge over a road, and the long siding returns from somewhere further north.
There are signal bridges with three-head signals, crossovers, and extra track on the north side at West Cumbo (MP 105.0), where the long siding ends and the speed limit is 60-50, signals and a crossover at Pearson Yard (MP 104.0), into the yard on the east side of the line, a track that diverges to the east, with a road bridge overhead between the switch and the divergence, a wide road bridge overhead, a bridge over I-81, Fawver, where the speed limit is 50-45, Intermediate Signals at Dry Run, a spur heading away east, a grade crossing, CV Conn. (MP 100.9), where the speed limit falls to 40 mph, a connector heads south onto the Winchester & Western's former PRR line to the south, and Intermediate Signals, and the main line turns southeast past MARC storage tracks on south side west of the station, Miller Tower on the northeast side, the passenger station at Martinsburg (MP 99.9, depot on the southwest side of the line, roundhouse on the northeast side, second roundhouse burned down in 1990, pedestrian bridge being built between depot and roundhouse), outer end of MARC service from Washington, DC, where the speed limit rises to 45-40,a bridge over a street, east of the depot, and signals on a signal bridge at NA Tower (MP 99.8), where it makes a connection with the Frog Hollow Industrial Track on the south side.
Continuing southeast, with speed limit 65-50, the line passes a road alongside to the northeast, a grade crossing with that road, a bridge over a stream, a grade crossing, Vanclevesville, where it turns south with speed limit 50-45 from MP 97.0 to MP 96.7 and then 50 mph to MP 95.9, where 65-50 resumes, a road alongside to the east, detectors at MP 95.6, Intermediate Signals at VA, a grade crossing, Intermediate Signals at MP 92.8, Kearneysville, where it turns southeast with speed limit 50-45 on the curve, a road alongside to the northeast, Intermediate Signals at "Rutherford", a closed grade crossing, Intermediate Signals at Hobbs (MP 90.2), where it turns east, a road bridge overhead, a grade crossing, signals (for the upcoming connector and crossover), and a grade crossing.
The former N&W line passes overhead, with a southeast quadrant connector trailing in at the crossover at Shenandoah Junction (MP 88.9), speed limit 50-45 at the junction, signals, a second crossover, more signals, a MARC station platform, grade crossing, and Intermediate Signals at Duffields (MP 87.9), where the speed limit is 60-50, falling to 45-40 at MP 85.3, a road alongside to the north, a turn southeast before Intermediate Signals at Eagle, two grade crossings and a road alongside to the north, with speeds falling to 40-35 at Intermediate Signals (signal bridge) at MP 83.2, rising to 45-40 at MP 82.0, and a grade crossing.
At Harpers Ferry (MP 81.3), the line reaches the river again, with passenger station and depot, restored to its 1928 appearance, on the southwest side below the town and an apparently derelict shelter on the north side, and turns east across the Potomac, with the Shenandoah line trailing in from the southwest at the east end of the through girder bridges, across the remains of the Chesapeake & Ohio canal, now a National Park, and a road on the north side of the river, and directly into Harper's Ferry Tunnel on the north side of the river, with speeds 60-40, along the north bank of the river past the C&O canal remains on the river bank, but the road on the north side of the line (having passed beneath the line), signals (labeled "D" on a plate on the signal mast) at Sandy Hook, with speeds dropping to 40-35 at MP 79.7, and a road bridge overhead (and over the river), curving just north of east past MP 79, a bridge over a stream, a road alongside to the north, a dirt road grade crossing, and a bigger road alongside to the north, to the signals and crossovers at Weverton (MP 78.8), leading to two pairs of tracks, a signal bridge with new signals, and a smaller road alongside to the north..
Speeds rise to 60-40 at MP 78.0, and the two pairs of tracks continue past Knoxville, and then separate, with the southerly pair used by eastbound trains and the northerly pair used by westbound trains. There is a road bridge overhead and the MARC passenger station at Brunswick (MP 75.7) has a platform on the north side of the southerly pair of tracks, a parking lot north of that, and the northerly pair of tracks beyond that. A connector curves away, east of the station, on the north side of the south pair of tracks to join the north pair (permitting westbound MARC trains to use the platform?). The Brunswick Yard starts at WB Tower (MP 75.6), with the two fans of ten yard tracks each between the two pairs of main tracks, past UN Office (MP 75.5), with the yard ending, and the north pair of tracks returning, reducing to a single track, and then trailing in, west of the crossovers at East Brunswick (MP 73.1).
There are detectors at MP 72.1, a bridge over a stream, Catoctin (MP 71.8), where the line turns south, MP 70.8 to MP 70.2, where the speed limit is 40 mph, the more northerly track passes through a pair of tunnels while the more southerly runs alongside a rock wall to their south/west, rising to 60-40 from MP 70.2 to 69.4, a road bridge overhead, a street alongside to the north/east, signals with "D" plates, and crossovers at Point of Rocks (MP 68.7), where the speed limit is 30 mph, the Old Main Line diverges to the east-northeast and the main line turns southeast, with the brick depot in the apex between the diverging lines. There's a single-track east leg of the wye, passing east of the depot.