Tobu Kameido Line

Tobu Railway was founded in 1897 to link Tokyo with Saitama, Gunma and Tochigi prefectures. The company at first planned to extend its line from its Honjo (Narihirabashi) starting point toward Etchūjima near Tokyo Bay, but the Etchūjima–Honjo–Senju stretch required careful review and its licence was slow to come. Tobu therefore opened its first section, from Kita-Senju on the Nippon Railway coastal line (today JR's Jōban Line) to Kuki, in August 1899. It then resubmitted its application for the Kita-Senju–Etchūjima line, adding a branch from around Shimo-Ōhata (near Hikifune) to Koume-kawaramachi — opened as Azumabashi Station, later Asakusa Station and now Tokyo Skytree Station — and a branch from Kameido to Honjo.

The licence was granted in June 1900, and as part of it the Kita-Senju–Azumabashi section opened in 1902 and the Kameido–Hikifune section on 5 April 1904. At opening the only intermediate station was Tenjin, and the line was unelectrified and steam-operated. On the same day Tobu began through services over the Sōbu Railway (the forerunner of today's JR Sōbu Main Line) from Kameido to Ryōgokubashi (now Ryōgoku), running into the newly opened Ryōgokubashi terminus. With this, Tobu abandoned its own Azumabashi–Hikifune section, the Kameido–Hikifune line took on the role of Tobu's main line, and the now-redundant Kameido–Honjo licence was cancelled in September of that year.

After the Sōbu Railway it ran into was nationalised in 1907, Tobu decided to move its terminus back to Azumabashi. The Azumabashi–Hikifune section reopened as a freight line in March 1908, and when Azumabashi was renamed Asakusa and passenger service resumed there in March 1910, the Kameido–Hikifune line reverted to branch status. Through passenger running onto the Sōbu Main Line ended on 27 March 1910, although freight trains for Ryōgokubashi continued to use the Kameido Line via Kita-Senju. The long-held ambition to push on from Kameido to Etchūjima was never realised — the licence lapsed in August 1910 as the intended right-of-way urbanised — and a later replanned extension toward Nishi-Hirai also went unbuilt. In 1918 the whole line was reclassified as a light railway.

In July 1926 the national railways opened the Shinkin freight cut-off line linking Shin-Koiwa on the Sōbu Main Line with Kanamachi on the Jōban Line, which ended all through freight from the national railways over the Kameido Line and left it a purely local route. When the whole line was electrified in 1928, a cluster of new intermediate stations opened, and the line came to have as many as seven intermediate stops. The Second World War reversed this growth: air raids, above all the Tokyo air raid of 10 March 1945, inflicted severe damage, and more than half of the line's stations were abolished or suspended. Several were never rebuilt, and post-war consolidations reduced the line to its present small set of stops.

After the war, ridership grew with the development of the districts along the parallel Isesaki Line. That trend reversed from 31 May 1962, when through running began between the Isesaki Line and the Teito Rapid Transit Authority (now Tokyo Metro) Hibiya Line, reshaping commuting routes into central Tokyo and drawing passengers away from the Kameido Line. A second such shift came on 19 March 2003, when the Hanzomon Line was extended to Oshiage and began through services with the Isesaki and Nikkō lines; a timetable revision at the same time cut weekday morning frequencies on the Kameido Line.

The line settled into its modern role as a self-contained shuttle. Driver-only (one-man) operation began on 19 October 2004, after which its rolling stock came to be worked in common with the similarly converted Tobu Daishi Line. Station numbering with the prefix "TS" was introduced across all stations on 17 March 2012. Today two-car trains shuttle between Hikifune and Kameido at intervals of roughly seven to eight minutes in the weekday morning peak and about ten minutes at other times, serving the dense low-lying neighbourhoods of Sumida and Kōtō wards, all of which sit in Tokyo's zero-metre-elevation belt.

• 19045 April: the Hikifune–Kameido section (3.4 km) opens; Tobu begins through running over the Sōbu Railway to Ryōgokubashi (now Ryōgoku). At opening the only intermediate station is Tenjin and the line is steam-operated.
• 19056 July: Tenjin Station is suspended.
• 19071 September: the Sōbu Railway is nationalised and becomes the Sōbu Main Line; through running from the Kameido Line continues.
• 19084 April: Tenjin Station is abolished, leaving the line with no intermediate stations.
• 191027 March: through passenger running onto the Sōbu Main Line ends; the Kameido–Hikifune line reverts to branch status after Asakusa (former Azumabashi) resumes passenger service.
• 191827 March: the whole line is reclassified as a light railway under the Light Railway Act.
• 19254 September: Tenjin Station reopens.
• 19261 July: the national railways open the Shinkin freight cut-off line (Shin-Koiwa–Kanamachi), ending all national-railway through freight over the Kameido Line and leaving it a purely local route.
• 192815 April: the whole line is electrified; six intermediate stations open at the same time (Kameido Suijin, Kitajikken, Hiraigaidō — now Higashi-Azuma — Omurai, Jukkenbashidōri and Torahashidōri).
• 194326 December: Torahashidōri Station is suspended.
• 194510 March: the Tokyo air raid abolishes Torahashidōri and Hiraigaidō stations and suspends Kitajikken and Jukkenbashidōri stations.
• 19465 December: Kitajikken and Kameido Suijin stations are relocated and merged into a single Kameido Suijin Station; Kitajikken is abolished.
• 195620 May: Higashi-Azuma Station opens on the site of the former Hiraigaidō Station (effectively a reopening); Tenjin Station is suspended on 31 October.
• 195720 May: Tenjin Station is abolished.
• 195822 October: Jukkenbashidōri Station is abolished.
• 196231 May: through running begins between the Isesaki Line and the Teito Rapid Transit Authority (now Tokyo Metro) Hibiya Line, reshaping commuting routes and reducing Kameido Line ridership.
• 200319 March: the Hanzomon Line is extended to Oshiage with through running to the Isesaki and Nikkō lines; a concurrent timetable revision cuts weekday morning frequencies on the Kameido Line.
• 200419 October: driver-only (one-man) operation begins on the line.
• 201217 March: station numbering with the prefix "TS" is introduced at all stations on the line.