Unused construction is also present near the west end of the Queensboro Bridge. The original plan there was to build two one-track tunnels under 59th and 60th Streets, rising onto the bridge to Queens. However, on July 28, 1915, the Public Service Commission approved a change of plans requested by the New York City Board of Estimate to place both tracks under 60th Street and cross the East River in the 60th Street Tunnel, because of concern whether or not the bridge could handle the weight of all-steel subway trains. A piece of the 59th Street tunnel had already been built, concurrent with the construction of the IRT Lexington Avenue Line, and became a walkway connecting the two side platforms of the IRT's 59th Street station.