I'm going to flush out the details on several of the more interesting suggestions I made in red. First, on the far left of the map, the straight red line directly tangent to the track. That's an extension of the Fitchburg Cutoff Bikepath, which currently helps give Belmont a straight shot to the subway. However, in order to get from Belmont center to the [path, you have to bike along a street, which has neither bike lanes or a cycle track. This proposal be very cheap, as the Fitchburg Line was originally four tracks wide, meaning there's plenty of space for the trail. The second proposal, and by far the most useful, are the two bridges across the Fitchburg line in the middle of the shot. These bridges would work to create a street grid, allowing people living near Fresh Pond drastically reduced time to the station, and allowing the kids who live at Rindge Towers (the public housing beside Alewife) a safe route to the school off the the bottom of the picture. The final one, which is the most complicated and least useful, is a series of paths allowing a parallel route Arlington Ctr-Alewife, next to the existing Minuteman Commuter Bikeway. The main attractiveness is for redundancy: in the event that the bikeway fails, traffic can be diverted to ensure people still have a safe commute. However, the high cost of tunneling under route two and possible wetlands issues put this a distant third priority.