Kotoden Shido Line

The line was the first railway built to link Takamatsu with the town of Shido, and it was opened not by the state railway but by the Tōsan Electric Tramway (Tōsan Denki Kidō). The first section opened on 18 November 1911 between Imabashi and Shido — the station now called Kotoden-Shido — and was electrified at 600 V DC. The railway was then extended back toward central Takamatsu in stages: the Dehare–Imabashi section, near what is now the Shido Line side of Kawaramachi, opened on 15 October 1913, and the Kōen-mae–Dehare section followed on 22 April 1915, the day Kawaramachi's site first came into use.

The young tramway soon passed through a series of corporate owners, the pattern of regional consolidation typical of Japan's small private railways. On 25 December 1916 the Tōsan Electric Tramway was absorbed by Shikoku Hydroelectric (Shikoku Suiryoku Denki), which marketed the line as the "Shikoku Hydroelectric Yashima excursion tram" and over 1917 extended the inner, street-running section through to Takamatsu Station and the harbour at Chikkō-mae. On 30 April 1942 Shikoku Hydroelectric transferred its railway business to the Sanuki Electric Railway (Sanuki Dentetsu).

The wartime years brought the line under the Kotoden name and gave it the shape it has today. On 1 November 1943 three local companies — the Sanuki Electric Railway, the Kotohira Electric Railway and the Takamatsu Electric Tramway — merged to form the Takamatsu-Kotohira Electric Railroad, the Kotoden group to which the line still belongs. At the same time Shido-eki-mae Station was renamed Kotoden-Shido, and the route was divided: the Chikkō-mae–Kōen-mae portion became the City Line, while Kōen-mae–Kotoden-Shido became the Shido Line.

The last years of the war cut the line back severely. On 26 January 1945 the outer Yakuri–Kotoden-Shido section was designated a "non-urgent line," suspended and stripped of its materials for the war effort. On 4 July 1945 the inner Kōen-mae–Dehare section was suspended along with the City Line because of air-raid damage, and on 30 July the burned-out Dehare Station was abolished, its functions consolidated into the Kotohira Line's Kotoden-Takamatsu Station. The suspended outer section was restored only on 9 October 1949, when Yakuri–Kotoden-Shido reopened.

Through the post-war decades the line settled into a local-transport role and was steadily knitted back into the wider Kotoden network. On 20 October 1953 through-running began to the Kotohira Line's Chikkō (a temporary station, the present Takamatsu-Chikkō), giving Shido Line trains a direct run to the harbour by reversing at Kawaramachi; the Kotoden-Takamatsu hub was renamed Kawaramachi on 1 January 1954. The long-suspended inner Kōen-mae–Kawaramachi section was formally abolished on 15 August 1957, following the closure of the City Line earlier that year. On 2 August 1966 the overhead voltage of the whole line was raised from 600 V to 1,500 V, matching the rest of Kotoden, and in 1969 the Kotoden-Yashima–Yakuri stretch was rerouted and Furu-Takamatsu Station moved in connection with construction of the Takamatsu northern bypass.

Safety and modernisation marked the line's later twentieth century. On 1 August 1976 a head-on collision near Imabashi injured 224 people; it was the first accident to force Kotoden to scrap rolling stock other than through war damage, and the only one caused by the company's own fault. Automatic train stop (ATS) was installed on 1 March 1979. The line's defining modern change came on 26 June 1994, when reconstruction of Kawaramachi Station severed the Shido Line from the Kotohira and Nagao lines: the through-service to Takamatsu-Chikkō was abolished and the Shido Line became an isolated line, disconnected from the rest of the Kotoden network.

Since its isolation the Shido Line has been operated as a self-contained route with its own fleet. Its first air-conditioned car, a 600 series, entered service on 13 July 1998, and on 31 July 2007 the line reached 100 percent air-conditioning, by which point its entire fleet consisted of former Nagoya municipal subway cars. Because the line is cut off from the rest of the system, ordinary inspections are carried out at the Imabashi Works next to Imabashi Station, while heavy overhauls require cars to be moved by road trailer to the Busshōzan Works. On 16 April 2022 one-man operation began across the whole line. Today the Shido Line carries two-car standard-gauge electric multiple units at roughly twenty-four-minute intervals, linking central Takamatsu with its eastern coastal suburbs and the temple town of Shido.

• 191118 November: the Tōsan Electric Tramway opens the first section, Imabashi–Shido (now Kotoden-Shido), electrified at 600 V DC.
• 191315 October: the Dehare (near present Kawaramachi)–Imabashi section opens.
• 191522 April: the Kōen-mae–Dehare section opens; the site of Kawaramachi Station first comes into use.
• 191625 December: Shikoku Hydroelectric (Shikoku Suiryoku Denki) absorbs the Tōsan Electric Tramway, marketing the line as the 'Shikoku Hydroelectric Yashima excursion tram'.
• 194230 April: Shikoku Hydroelectric transfers its railway business to the Sanuki Electric Railway (Sanuki Dentetsu).
• 19431 November: the Sanuki Electric Railway, the Kotohira Electric Railway and the Takamatsu Electric Tramway merge to form the Takamatsu-Kotohira Electric Railroad (Kotoden); Shido-eki-mae is renamed Kotoden-Shido, and Kōen-mae–Kotoden-Shido becomes the Shido Line.
• 194526 January: the outer Yakuri–Kotoden-Shido section is designated a 'non-urgent line', suspended and stripped of materials for the war effort.
• 19454 July and 30 July: the inner Kōen-mae–Dehare section is suspended with the City Line because of air-raid damage; the burned-out Dehare Station is abolished and consolidated into the Kotohira Line's Kotoden-Takamatsu Station.
• 19499 October: the suspended Yakuri–Kotoden-Shido section is restored and reopens.
• 195320 October: through-running begins to the Kotohira Line's Chikkō (a temporary station, the present Takamatsu-Chikkō), with trains reversing at Kawaramachi.
• 19662 August: the overhead voltage of the whole line is raised from 600 V to 1,500 V, matching the rest of Kotoden.
• 19761 August: a head-on collision near Imabashi injures 224 people — the first accident to force Kotoden to scrap rolling stock other than through war damage, and the only one of the company's own fault.
• 19791 March: automatic train stop (ATS) is installed.
• 199426 June: reconstruction of Kawaramachi Station severs the Shido Line from the Kotohira and Nagao lines; through-running to Takamatsu-Chikkō is abolished and the line becomes an isolated line.
• 200731 July: the line reaches 100 percent air-conditioning, its entire fleet by then consisting of former Nagoya municipal subway cars.
• 202216 April: one-man operation begins across the whole line.