I’ve always thought that the PATH ROW has now fully been disconnected from Amtrak’s Northeast Corridor. However I believe that there are still some switched that allow PATH to merge into Amtrak’s main line on PATH’s southbound track. The switches are clearly visible in this map: http://broadway.pennsyrr.com/Rail/Prr/Maps/Itlk/dock.gif It was rebuilt in May 22, 1937 when Manhattan Transfer was removed and the last revision of the DOCK interlock was of April 29,1967 unless there has been another revision recently.