Commuter rail networks outside of densely populated urban areas like the Washington ., New York, Chicago, Philadelphia, Boston, San Francisco, Montreal, and Toronto metropolitan areas have historically been sparse. Since the 1990s, however, several commuter rail projects have been proposed and built throughout the United States, especially in the Sun Belt and other regions characterized by urban sprawl that have traditionally been underserved by public transportation. Since the late 1990s, commuter rail networks have been inaugurated in Dallas, San Diego, Minneapolis, Nashville, Salt Lake City, Orlando, and Albuquerque, among other cities. Several more commuter rail projects have been proposed and are in the planning stages.
In July 1945, the terminal of the Keiō Line was relocated to the present location, though on the ground level, on the west side of Shinjuku Station. Keiō Shinjuku Station and Shōsen Shinjuku Ekimae Station were closed. This was because the trains faced difficulty in climbing up the slopes of the bridge over the governmental railway after one of the nearby transformer substations was destroyed by an air raid . The site of Keiō Shinjuku Station near Shinjuku-Sanchōme subway station is now occupied by two buildings owned by Keiō: Keiō Shinjuku Sanchōme Building and Keiō Shinjuku Oiwake Building.