a segment shared by the Saikyō Line and Shōnan-Shinjuku Line. In this situation, the trackage is counted only once, under the Saikyō Line. Similarly, tabulations for the larger tram systems with a high degree of interlining, such as Hiroshima Electric Railway, also consider only unique segments, and sections where multiple routes overlap are only counted once. However, if there is some reasonable segregation of operations or distinction between lines, the trackage is counted more than once. Examples include the various quadruple-track sections of East Japan Railway Company (JR East) that provide segregated local and rapid services (e.g., Chūō Rapid Line vs. Chūō-Sōbu Line). Here, the route-kilometers are counted twice, once under the Chūō Rapid Line and again under the local Chūō-Sōbu Line. Other situations include quadruple-track sections at the confluence of two distinct double-track lines, such as the Ōsaka Uehommachi – Fuse quadruple-track section of the Kintetsu network in central Ōsaka, officially designated as part of the Osaka Line but actually two lines (the Osaka Line and Nara Line) sharing a single right-of-way west of Fuse. A similar situation applies for many JR East lines—the Yamanote Line and Keihin-Tōhoku Line officially use tracks classified as part of the Tōkaidō Main Line and Tōhoku Main Line, but that are fully segregated from the tracks used by the respective services operating under the names "Tōkaidō Line" and "Utsunomiya Line" / "Takasaki Line". Cross-company considerations As a general rule, trackage used by one company but owned by another company as part of a trackage rights or (often translated as through-service) agreement is not counted under the first company. For example, trackage on the Toei Asakusa Line is not counted under Keikyu Corporation, Keisei Electric Railway, or the Hokusō Railway, despite the fact that all three operate their trains on the Asakusa Line. However, this list makes some exceptions to this rule, the most notable being the Keisei-Takasago – Inba-Nihon-Idai section of the Keisei Narita Airport Line, which is shared with trains operated by Hokusō Railway but owned partially by Hokusō Railway (Keisei-Takasago – Komuro) and Chiba New Town Railway (Komuro – Inba-Nihon-Idai). This shared trackage is counted once under Hokusō Railway and again under Keisei Electric Railway. Similar exceptions include trackage owned by third-sector railways that do not own any of their own rolling stock and instead contract out train operations to through-servicing operators. Notable examples include the double-track approach into Narita Airport,