In 2015 and 2016, when estimated costs were spiraling out of control, the MBTA proposed to save money by eliminating the pathway from the project's scope.
But hundreds of local advocates and Somerville elected officials lobbied to keep it in the scope of the project.
The GLX project began construction at the end of 2017. Its two light rail extensions opened in March and December 2022.
The new path runs alongside the new Green Line tracks for a little over two miles. It connects downtown Boston and the Charles riverfront through several Somerville neighborhoods to the Alewife area in Cambridge, where several other popular multi-use trails converge.
The path is also a segment in the much longer Mass. Central Rail Trail, a partially-complete 100-mile pathway between Boston and Northampton.