Wilmington and Wilmington Junction to Lowell Junction

From the junction with the Lowell Line (MBTA New Hampshire Route Main Line) at Wilmington (MP 15.2), where the Lowell Line turns northwest, the Wildcat Branch heads north, single track, CTC, with speed limit 20 mph for both passenger and freight trains, past the grade crossing at Main Street (MP 15.4), a wooded area, the grade crossing and 2,020 ft. siding at Clark Street (MP 15.7), where the speed limit rises to 25 mph, the grade crossing at Glen Road (MP 16.2), a box labeled "B17" on the east side, and the grade crossing at Salem Street (MP 17.3), to Wilmington Junction (CPW-WJ, MP 18.7/17.92), where the Wildcat Branch trails into the west side of the MBTA Western Main Line and a freight line between Lowell and Salem once crossed east-west.

The Haverhill Line heads north, single track, CTC, speed limit 60 mph for passenger trains and 40 mph for freight trains, past a road bridge overhead, an old spur on the east side, and the grade crossing at Lowell Junction Road (MP 19.5), to Lowell Junction (CPF-LJ, MP 19.57), where the Western Main Line (Haverhill Line) trails into the south side of the former GTI Freight Main Line, coming from the west, and the combined line heads just east of due north.