Watertown Branch Railroad

Construction of an extension to Fresh Pond Reservation in Cambridge began in the summer of 2018 and was completed in June 2022.

In order to keep it out of the hands of its rivals, the Fitchburg took control of both companies before any track was laid and merged them into the Watertown Branch.

[3]: 154  In the Fresh Pond area it paralleled the existing Charlestown Branch Railroad which was used to haul ice.

On October 5, 2011, the Surface Transportation Board agreed to allow Pan Am Railways to abandon the final active 1.72 miles of the Watertown Branch from Newly Weds Foods in Watertown to the branch's junction with the Fitchburg Line between Sherman Street and Alewife in Cambridge.

The condition of the tracks at that time was deemed so poor that trains traveling at a mere 3 miles per hour (4.8 km/h) could derail.

[15] This trail segment was later transferred administratively to the MDC, currently known as the Massachusetts Department of Conservation and Recreation (DCR).

[18] In 2015, the DCR obtained $180,000 to fund design of the remaining greenway section, half from private donations.

[21] Funding of $3.6 million was approved by the Boston Region Metropolitan Planning Organization (MPO) in June 2017, with construction projected to start in Fall 2017 or Spring 2018.

The branch line proceeds west, and then south, where it has at-grade crossings at New Street, Concord Avenue, and the entrance road to the Walter J. Sullivan Water Treatment Facility at the Fresh Pond reservoir.

From there, the line proceeds to several underpasses, namely one below a second road into the Fresh Pond reservation, one at Huron Avenue, and one at Mount Auburn Street, where it then crosses the town boundary of Watertown.

It then reached the Central Square area, and looped back into the Fitchburg Railroad main line.

[21] Planned renovations at the Arsenal Mall are expected to include a connection to the Charles River Bike Path.