Back Bay to Framingham

From the passenger station with  two side platforms beneath an air-rights building above, with the two side platforms of the Orange Line alongside to the north, down in a trench, with the MBTA Orange Line alongside to the north at Back Bay (MP 227.6/1.2), west of which, in the "tunnel" formed by the air-rights construction overhead, the Amtrak line swings south-southwest while the former Conrail line continues just south of due west, double track, CTC, speed limit 30 mph, past a major highway alongside to the north, four road bridge overhead, the MBTA passenger station at Yawkey (MP 2.5),  where the speed limit rises to 40 mph, Sewell's Point, where a line to Newton once left to the southwest and the main line turns northwest, an angled road bridge overhead, two road bridges overhead, and an angled road bridge overhead.

The line turns west and reduces to single track at Allston/CP-3 (MP 3.1), east end of the 12-track Beacon Park Yard on the north side, where the highway on the north side rises up over the east end of the yard and then curves away northwest the passenger speed limit rises to 50 mph, and the East Boston branch trails in from the northeast at a wye on the north side of the yard, past a yard tower on the north side near the west end, an angled road bridge overhead, the highway alongside to the north again, two extra tracks to the north and one alongside the main line, trailing in at Brighton/CP-4 (MP 4.8), west end of the yard, where the line expands to double track, again, and the passenger speed limit rises to 60 mph.

There is a road bridge overhead, several bridges over streets (also bridged by the highway to the north), Intermediate Signals at MP 6.x, a road bridge overhead as the highway crosses, a street alongside to the north, a cutting with stone walls, a road bridge overhead, the highway alongside to the south, four road bridge overhead, an MBTA passenger station with north side platform at Newtonville (MP 8.1), a road bridge overhead, extra track on the north side at a factory, Intermediate Signals, an MBTA passenger station with south side platform at West Newton (MP 9.1), a road bridge overhead, a street to the north, a road bridge overhead, an angled road bridge overhead, an MBTA passenger station with south side platform at Auburndale (MP 10.2), a turn south-southwest with a passenger speed restriction of 55 mph between MP 10.4 and MP 10.7, reverting to 60 mph thereafter, a bridge over a river, Riverside (MP 10.6), where a branch to Newton once headed away southeast, a bridge over a road, and a bridge over an Interstate.

Signals at CP-11 (MP 11.4) are followed by a passenger speed restriction of 55 mph between MP 11.5 and MP 12.2, reverting to 60 mph thereafter, an MBTA passenger station with south side platform at Wellesley Farms (MP 12.5), where the line turns southwest, two road bridges overhead, a passenger speed restriction of 55 mph on Track 1 between MP 13.4 and MP 13.6, in a wooded valley, an MBTA passenger station with south side platform at Wellesley Hills (MP 13.5), where the line turns west-southwest, an MBTA passenger station with north side platform at Wellesley Square (MP 14.7), Intermediate Signals at MP 16.x, a river alongside to the north, a street to the north, a rocky cutting, a road bridge overhead, and an MBTA passenger station with north side platform at Natick (MP 17.7), where the line turns west and Saxonville Industrial Track heads away north.

There are two road bridges overhead, woods and fields, a river to the north, Intermediate Signals at MP 18.x, two road bridges overhead, a street to the north, a road bridge overhead, an MBTA passenger station with north side platform at West Natick (MP 19.9), a grade crossing, a street alongside to the north, a speed restriction of 30 mph between MP 20.9 and CP-22, a signal bridge, the junction at CP-21 (MP 21.3), where the Framingham Secondary from Mansfield trails in from the southeast and continues northwest, across the line, to East Fitchburg, a street alongside to the south, a box labeled "21" on the north side, an MBTA and Amtrak passenger station, with two side platforms, umbrella sheds and pedestrian bridge at Framingham (MP 21.4), a track trailing in on the north side, and the junction at CP-22 (MP 21.7), where the Holliston Industrial Track  heads south and the main line heads west-southwest.