Japan operates a variety of or or through trains which are direct seamless connections between rail operators, using leased trackage rights and junctions, to cut cross metropolitan area commutes without having to change trains, wait, figure out connections, or cross platforms/stations. Most of these junctions have been constructed well after the lines have been operating. Some far-flung spur lines have been shortened (abandoned stations and track due to low patronage); through service is a frequently used method to integrate the surviving short stub lines into multiple rail operator's systems, enhancing convenience and ridership. Through-service proliferation is increasingly common phenomenon as the railway networks, urban density (and Japan's demographics) have matured and new line construction is minimal.
There are several dozen unique through service runs in Japan, the actual track usage details are complex (but as a seamless service offers an abstraction layer for the end user), the Japanese Wikipedia page has a . Standardization is required for cross railway services, in terms of rolling stock dimensions, rail gauge, overhead power, not to mention coordinated scheduling between a mixture of separate companies and/or government agencies.
Through services in Japan are commonly of two types: unidirectional or bidirectional (unidirectional trains return empty on non-circular tracks). The first usage of through services was on the Tobu Kameido Line in 1904, but was suspended in 1910. Japan's first modern (postwar) through services began in 1960, from the Toei Asakusa Line to Keisei Oshiage Line.
There are also through services that have been discontinued (not listed here).
List of existing services (passenger)
- Asakusa Line : Misakiguchi Station, Uraga Station, Zushi÷Hayama Station, Haneda Airport Domestic Terminal Station or Nishi-magome Station to Narita Airport Terminal 1 Station(via Keisei Narita Airport Line or Keisei Main Line) or Shibayama-Chiyoda Station (e.g., 85.4 km from Haneda Airport Domestic Terminal to Narita Airport Terminal 1 via Keisei Narita Airport Line)
- 1.KeikyÃ
« Kurihama Line 13.4 km (Misakiguchi to Horinouchi)
- 2.KeikyÃ
« Main Line 4.4 km (Uraga to Horinouchi)
- âÂÂ=1. and 2. merged at Horinouchi StationâÂÂ=
- 2.KeikyÃ
« Main Line 11.4 km (Horinouchi to Kanazawa-hakkei)
- 3.KeikyÃ
« Zushi Line 5.9 km (Zushi÷Hayama to Kanazawa-hakkei)
- âÂÂ=2. and 3. merged at Kanazawa-hakkei StationâÂÂ=
- 2.KeikyÃ
« Main Line 32.9 km (Kanazawa-hakkei to KeikyÃ
« Kamata)
- 4.KeikyÃ
« Airport Line 6.5 km (Haneda Airport Domestic Terminal to KeikyÃ
« Kamata)
- âÂÂ=2. and 4. merged at KeikyÃ
« Kamata StationâÂÂ=
- 2.KeikyÃ
« Main Line 9.2 km (KeikyÃ
« Kamata to Sengakuji)
- 5.Toei Asakusa Line 6.9 km (Nishi-magome to Sengakuji)
- âÂÂ=2. and 5. merged at Sengakuji StationâÂÂ=
- 5.Toei Asakusa Line 11.4 km (Sengakuji to Oshiage)
- 6.Keisei Oshiage Line 5.7 km (Oshiage to Aoto)
- âÂÂ=5. and 6. connected at Oshiage StationâÂÂ=
- âÂÂ=6. and 7. connected at Aoto StationâÂÂ=
- 7.Keisei Main Line (from Keisei Ueno Station) 1.2 km (Aoto to Keisei-Takasago)
- âÂÂ=8. branched from 7. at Keisei-Takasago StationâÂÂ=
- 8.Keisei Narita Airport Line 51.4 km (Keisei-Takasago to Narita Airport Terminal 1)**** 7.Keisei Main Line 48.5 km (Keisei-Takasago to Keisei Narita)
- âÂÂ=9. branched from 7. at Keisei Narita StationâÂÂ=
- 7.Keisei Main Line 8.1 km (Keisei Narita to Narita Airport Terminal 1)
- 9.Keisei Higashi-Narita Line 7.1 km (Keisei Narita to Higashi-Narita)
- âÂÂ=9. and 10. connected at Higashi-Narita StationâÂÂ=
- 10.Shibayama Railway Line 2.2 km (Higashi-Narita to Shibayama-Chiyoda)
- Mita Line : Ebina Station to Nishi-Takashimadaira Station (67.7 km)
- SÃ
Âtetsu Main Line 17.7 km (Ebina to Nishiya)
- SÃ
Âtetsu Shin-yokohama Line 6.3 km (Nishiya to Shin-Yokohama)
- TÃ
ÂkyÃ
« Shin-yokohama Line 5.8 km (Shin-Yokohama to Hiyoshi)
- TÃ
ÂkyÃ
« Meguro Line 11.9 km (Hiyoshi to Meguro via Den-en-chÃ
Âfu)
- Toei Mita Line 26.5 km (Meguro to Nishi-Takashimadaira via Shirokane-Takanawa)
- Mita Line : ShÃ
Ânandai Station to Nishi-Takashimadaira Station (64.9 km)
- SÃ
Âtetsu Izumino Line 11.3 km (ShÃ
Ânandai to Futamatagawa)
- SÃ
Âtetsu Main Line 3.6 km (Futamatagawa to Nishiya)
- SÃ
Âtetsu Shin-yokohama Line 6.3 km (Nishiya to Shin-Yokohama)
- TÃ
ÂkyÃ
« Shin-yokohama Line 5.8 km (Shin-Yokohama to Hiyoshi)
- TÃ
ÂkyÃ
« Meguro Line 11.9 km (Hiyoshi to Meguro via Den-en-chÃ
Âfu)
- Toei Mita Line 26.5 km (Meguro to Nishi-Takashimadaira via Shirokane-Takanawa)
- Shinjuku Line : Takaosanguchi Station to Motoyawata Station (68.2 km)
- KeiÃ
 Takao Line 8.6 km (Takaosanguchi to Kitano as local train or Express)
- KeiÃ
 Line 32.5 km (Kitano to Sasazuka via ChÃ
Âfu as local train, Rapid, Semi-Express or Express)
- KeiÃ
 New Line 3.6 km (Sasazuka to Shinjuku)
- Toei Shinjuku Line 23.5 km (Shinjuku to Motoyawata)
- Shinjuku Line : Hashimoto Station to Motoyawata Station (61.6 km)
- KeiÃ
 Sagamihara Line 22.6 km (Hashimoto to ChÃ
Âfu as local train, Rapid, Semi-Express or Express)
- KeiÃ
 Line 11.9 km (ChÃ
Âfu to Sasazuka as local train, Rapid, Semi-Express or Express)
- KeiÃ
 New Line 3.6 km (Sasazuka to Shinjuku)
- Toei Shinjuku Line 23.5 km (Shinjuku to Motoyawata)
- Tobu Railway
- NikkÃ
 Line : Shinjuku Station to TÃ
Âbu-NikkÃ
 Station (NikkÃ
 and Spacia NikkÃ
 limited express) (140.7 km)
- JR East Yamanote Freight Line 10.0 km (Shinjuku to Tabata)
- JR East TÃ
Âhoku Main Line 50.1 km (Tabata to Kurihashi)
- TÃ
Âbu NikkÃ
 Line 80.6 km (Kurihashi to TÃ
Âbu-NikkÃ
 via Shimo-Imaichi)
- NikkÃ
 Line : Shinjuku Station to Kinugawa-Onsen Station (Kinugawa and Spacia Kinugawa limited express) (146.0 km)
- JR East Yamanote Freight Line 10.0 km (Shinjuku to Tabata)
- JR East TÃ
Âhoku Main Line 50.1 km (Tabata to Kurihashi)
- NikkÃ
 Line 73.5 km (Kurihashi to Shimo-Imaichi)
- TÃ
Âbu Kinugawa Line 12.4 km (Shimo-Imaichi to Kinugawa-Onsen)
- NikkÃ
 Line : Asakusa Station to Aizu-Tajima Station (Section-Rapid or Rapid) (146.0 km)
- TÃ
Âbu Skytree Line 41.0 km (Asakusa to TÃ
Âbu-DÃ
Âbutsu-KÃ
Âen)
- TÃ
Âbu NikkÃ
 Line 87.4 km (TÃ
Âbu-DÃ
Âbutsu-KÃ
Âen to Shimo-Imaichi)
- TÃ
Âbu Kinugawa Line 16.2 km (Shimo-Imaichi to Shin-Fujiwara via Kinugawa-Onsen)
- Yagan Railway Aizu Kinugawa Line 30.7 km (Shin-Fujiwara to AizukÃ
Âgen-Ozeguchi)
- Aizu Railway Aizu Line 15.4 km (AizukÃ
Âgen-Ozeguchi to Aizu-Tajima)
- Odakyu Electric Railway
- Odawara Line : Shinjuku Station to Hakone-Yumoto Station (Homeway, Sagami, Hakone and Super Hakone Romancecar limited express) (104.4 km)
- Odakyu Odawara Line (Shinjuku to Odawara) 82.5 km
- Hakone Tozan Line 6.1 km (Odawara to Hakone-Yumoto)
- Odawara Line : Shinjuku Station to Gotemba Station (Asagiri Romancecar limited express) (96.8 km)
- Odakyu Odawara Line (Shinjuku to Matsuda) 71.8 km
- JR Central Gotemba Line (Matsuda to Gotemba) 25.0 km
- Sagami Railway
- SÃ
Âtetsu-JR Direct Line : Ebina Station to Shinjuku Station (57 km)
- SÃ
Âtetsu Main Line (Ebina to Futamata-gawa)
- SÃ
Âtetsu Shin-Yokohama Line (Futamata-gawa to Nishiya)
- SÃ
Âtetsu-JR Direct Line (Nishiya to Musashi-Kosugi)
- JR TÃ
ÂkaidÃ
 Main Line (Musashi-Kosugi to Ã
Âsaki)
- JR Yamanote Line (Ã
Âsaki to Shinjuku)
- Fuji Kyuko
- Fujikyuko Line : TÃ
ÂkyÃ
 Station to Kawaguchiko Station (114.4 km)
- JR East ChÃ
«Ã
 Main Line (TÃ
ÂkyÃ
 to Ã
Âtsuki) 87.8 km
- Fujikyuko Line (Ã
Âtsuki to Kawaguchiko) 26.6 km
Kyushu (Fukuoka)
Through services between JR companies
Services between JR railway lines and third-sector lines
Services between third-sector railways
References