The two trackways on the lower level were unused when the tunnel construction project was halted in the 1970s. They are planned to be used by the Long Island Rail Road's East Side Access project, which will bring LIRR commuter trains to Grand Central Terminal. During construction of the East Side Access project, the lower level of the 63rd Street Tunnel was used to transport equipment. The laying of permanent tracks started in September 2017. Due to low vertical clearances in the lower level, bilevel rail cars, such as the LIRR's C3 fleet, would not be able to serve Grand Central when the tunnel is complete.