 As soon as the Union Railroad was completed, the Northern Central Railway obtained the right to use it, and in February, 1882, the Northern Central purchased the Union Railroad stock from the Canton Company, and assumed control March 1 of the same year.Additional work was done on the tunnels between 1928 and 1935 to prepare for the electrification of the Pennsylvania Railroad's New York-Washington mainline.The original Union Tunnel, too small to accommodate overhead catenary on its two tracks, was supplemented by an adjacent double-track tunnel to the east, then converted to a single track which provided adequate clearance for electrification.