埼京線
The line runs parallel to the Yamanote Line between Ōsaki and Ikebukuro, where it is formally called the Yamanote Freight Line(), and as an alternate route to the Tōhoku Main Line between Akabane and Ōmiya, where it is unofficially called the Tohoku Honsen Secondary Line(). The portion between Ikebukuro and Akabane is officially known as the Akabane Line(). For most purposes, JR refers to all of these as part of the "Saikyō Line" when being used for Saikyō Line services.