The first proposals to bring LIRR service to a terminal in eastern Midtown Manhattan arose in 1963. To facilitate planning for this terminal, a third track was added to the plans for the 63rd Street subway tunnel in April 1966. The track would serve LIRR trains to east Midtown, alleviating train traffic into Penn Station on Manhattan's west side while integrating the LIRR with the subway. A fourth track was added to the plans in August 1966 after it was determined that LIRR trains would be too large to run on subway tracks. This amendment increased the number of LIRR tracks to two, and provided segregated tracks for the LIRR and the subway.