The Fairmount Line is the only T Commuter rail line that stays within the Boston city limits. It's also been neglected over the years with poor maintenance and limited stations through one of the more challenged neighborhoods in Boston. However there have been recent plans by the CDCs to add five or so stations and make this line a part of the rapid transit network and use the new station construction to get better service on the line as well as more opportunities for affordable housing. Because of the patterns of parcelization and built out nature of the corridor, it would be hard to expect a major renaissance but small progress is to be expected.
Better service would definitely improve the corridor too. It will be interesting to see how it works out. Recent planning and funding put forward by the Patrick administration suggests that this will be done soon but rejoicing should wait until its actually complete. For more information on this corridor, check out the report chapter by Reconnecting America that discusses tools and policies for revitalization. (Warning, 38MB)