With less than three months to go before it’s set to open, the Second Avenue Subway has reached another milestone. The Metropolitan Transportation Authority says test trains began running along the line between 63rd and 96th Street over the weekend. Below is YouTube footage taken from the publicly-accessible area of Lexington Avenue – 63rd Street. Under the first phase of the project, the Q train will be rerouted to Second Avenue and will run between 96th Street and Coney Island. The Second Avenue Subway is expected to start running with paying customers on December 31.