San Diego Association of Governments awarded the $57.9 million contract to Flatiron for the Metropolitan Transit System Blue Line Trolley Stations Improvement project to upgrade trolley stations, transit center, and track reconstruction between the San Diego Trolley Yard and San Ysidro Intermodal Transit Center. As one of the most heavily used transit service in the San Diego area with an average daily ridership of more than 50,000 people, the Blue Line is one of the most successful light rails transit (LRT) in North America.

Project work included reconstruction of 11 LRT station platforms to accommodate new low-floor vehicles that allow customers to board near-level. Additional station improvements include access between trolley and bus services, new shelters, closed circuit television, next-arrival signage, and enhanced lighting. Track infrastructure through and adjacent to each LRT station was removed and reinstalled including reconstruction of trackway concrete pavement; rail and tie replacement; highway grade crossings; barrier walls; and installation of drainage and water quality features. Outdated rail and overhead wires were replaced along with improvement of street crossings, switching, and signaling. Existing transit centers and parking facilities were reconstructed.