York, New Haven and Hartford Railroad, via Middletown and Willimantic New York and Connecticut Air Line Railroad (never built) New York and Pittsburgh Air Line Railroad New York and Washington Air Line Railway (never built) Niagara River and New York Air Line Railroad in New York (never built) Northern Air-Line Railroad in New York (never built) Northern Nebraska Air Line Railroad, part of the Chicago and North Western Railway Pennsylvania Railroad along New Jersey section of the Northeast Corridor Piedmont Air-Line Railway, part of the Southern Railway Quebec and Boston Air Line Railway (never built) Raleigh and Augusta Air-Line Railroad, part of the Seaboard Air Line Railroad Richmond and Washington Air Line Railroad (never built) Salamanca Air Line Railroad in New York Santa Monica Air Line in Los Angeles County Seaboard Air Line Belt Railroad (Atlanta, Georgia), part of the Seaboard Air Line Railroad Seaboard Inland Air Line Railroad, a predecessor of the SAL Southern New England Railway, Never completed. St. Charles Air Line Railroad in Chicago, Illinois St. Clair and Chicago Air Line Railroad, part of the Grand Trunk Railway St. Louis, Oklahoma and Texas Air-Line Railroad, part of the Chicago, Rock Island and Pacific Railroad Stillmore Air Line Railway, part of the Central of Georgia Railway Utica and Syracuse Air Line Railway in New York (never built) Virginia Air Line Railway, part of the Chesapeake and Ohio Railroad (defunct) Waycross Air Line Railroad, part of the Atlantic Coast Line Railroad References Rail infrastructure