The Massachusetts Bay Transportation Authority (MBTA) and the Massachusetts Department of Transportation (MassDOT) are jointly constructing an extension to the existing Green Line Light Rail Transit (LRT) route from a relocated Lechmere Station in Cambridge to College Avenue in Medford and Union Square in Somerville. The Green Line Extension (GLX) will operate on the exclusive right-of-way of the MBTA Commuter Rail System, adjacent to existing commuter rail service. The project includes six atgrade stations and one elevated station; 3.7 miles of at-grade guideway and one mile of elevated guideway; reconstruction of eight bridge structures to maintain grade separation on the route; and the purchase of 24 light rail vehicles.