Willows to Lowell Junction

From the junction at CPF-WL/Willows (MP 313.77/33.72), where the Fitchburg Line to Boston turns away on the south side of the former Boston & Maine Main Line to Mattawamkeag, the latter heads northeast, Two Main Tracks, CTC, maximum speed 40 mph, but with a local 10 mph speed restriction on Track 2 to CPF-312 (MP 311.97), where single track, CTC, starts and full line speed prevails, past Forge Village (MP 310.19) and CPF-309 (MP 309.19), where Two Main Tracks, CTC, resume, with a 10 mph speed restriction on Track 2 to CPF-307, turning east, past Graniteville, wehre an erstwhile line from Nashua to North Acton once crossed, northeast past CPF-307 (MP 307.35), where single track, CTC, starts, and West Chelmsford, and just north of due east past North Chelmsford, CPF-303 (MP 303.00), west leg of the wye (10 mph on the wye) with the Northern Main Line, where a 10 mph speed restriction starts, and the junction with the Northern Main Line from Nashua and beyond, trailing in from the north-northeast, at CPF-NC (MP 302.34/28.34), where Two Main Tracks, CTC, resume and full line speed prevails.

The line turns northeast, past MP 26.50, where a 30 mph speed restriction starts, and then south-southeast, past CPF-WA (MP 299.95/25.95), CPF-LO (MP 299.47/25.47), where Four Main Tracks, CTC, start, the passenger station at Lowell (MP 25.47), start of MBTA service to Boston, and the junction (20 mph on the junction) with the New Hampshire Route to Boston, heading away on the south side at CPF-BY (MP 298.50/24.66), where Two Main Tracks, CTC, resume, with a 30 mph speed restriction on Track 1 and a 10 mph speed restriction on Track 2, heading southeast, past CPF-297 (MP 296.50), where an erstwhile line to Salem once left on the south side, single track, CTC, starts and full line speeds (40 mph) prevail, turning just north of due east, past Tewkesbury (MP 294.82), where an erstwhile line between Salem Junction and Lawrence once crossed, and a 25 mph speed restriction on the curve between MP 291.64 and the junction with the Western Route Main Line from Boston, trailing in on the south side at CPF-LJ (MP 291.15/19.85), where the line heads north.