From the east end of Selkirk Yard, end of the Inbound Track, and the junctions with the Albany Secondary, to the north, and River Line, to the south, at Selkirk Junction/CP-SK (MP 11.5), the Selkirk Branch continues southeast, Two Main Tracks, Rule 261, maximum speed 30 mph, past a southeast quadrant connector from the River Line, trailing in on the south side, and turning east-southeast across the bridge over the Hudson River and the Hudson line, on the east side of the river, to CP-SM (MP 8.5), where the Boston Line continues ahead, and the Selkirk Branch turns south, single track, Rule 261, maximum speed 40 mph, past a detector at Hudson View (MP 5.0), and a bridge over the Hudson Line to its west side, before trailing in to the Hudson Line on the west side at Stuyvesant/CP-125 (MP 1.3).
The Boston Line continues east-southeast, single track, Rule 261, maximum speed 50 mph, from CP-SM (MP 191.8), past a detector at "Post Road" (MP 187.8) to the junction where the Post Road Branch trails in on the north side at CP-187 (MP 187.4).