The whole idea behind the Fairmount Line is to bring economic activity to the streets that surround the train tracks. Rising property prices should be an indication that the rail line has created something people want to be a part of. But that’s only if the trains are helping to create wealth in neighborhoods instead of just importing it and pushing aside existing residents in the process. And, as research from Northeastern University’s Dukakis Center for Urban and Regional Policy has shown, gentrification and displacement tend to follow closely behind transit expansion projects.