Tateyama Line

The present line is the product of several predecessor companies and a prefectural railway, knitted together over three decades. The oldest piece of the network was opened on 25 June 1913, when the Tateyama Light Railway (Tateyama Keiben Tetsudō) built a 762 mm gauge line between Namerikawa and Gohyakkoku — a stretch that today belongs to the Toyama Chihō Railway Main Line rather than the Tateyama Line itself. The company was renamed the Tateyama Railway in 1917.

The Tateyama Line proper began on 19 March 1921, when the Tateyama Railway opened the section from Gohyakkoku to a first-generation "Tateyama" station near present-day Iwakuraji — a station distinct from today's Tateyama terminus. In parallel, the prefectural railway (Toyama Prefectural Railway) opened the line up the valley from Iwakuraji: the Iwakuraji–Yokoe section opened on 11 October 1921 (Yokoe later became Kami-Yokoe, closed in 1997), and the line was pushed on to Chigaki by 1923. The prefectural section was electrified at 600 V DC in 1927.

Electrification and gauge standardisation followed in the 1930s. On 6 April 1931 the Tateyama Railway was absorbed by the Toyama Electric Railway, which on 15 August 1931 opened the Terada–Gohyakkoku section at 1,067 mm gauge, electrified at 1,500 V DC. The older Gohyakkoku–Iwakuraji segment was regauged to 1,067 mm and electrified at 1,500 V DC on 18 August 1936. The prefectural section was raised to 1,500 V DC in 1937, the same year the line was extended further up the valley toward Arimineguchi (the Chigaki–Awasuno section opening on 1 October 1937).

The modern operator was formed in the wartime consolidation of Toyama's railways: on 1 January 1943 the prefectural railway and the railway lines of the Japan Electric Generation and Transmission Company (Nippon Hassōden) were transferred to the newly created Toyama Chihō Railway, bringing these segments under one company. The upper reaches were completed after the war: the Awasuno–(provisional) Tateyama section opened on 1 August 1954, and the (provisional) Tateyama–Senjugahara section — Senjugahara being the present site of Tateyama Station — opened on 1 July 1955, while the Omi–Awasuno stretch had been transferred to the Tateyama Development Railway in 1954.

The line took its current name and shape in a network-wide reorganisation on 1 April 1969. The former Gohyakkoku Line was incorporated into the Tateyama Line, while the Inarimachi–Minami-Toyama segment was split off as the Fujikoshi Line and the Minami-Toyama–Iwakuraji segment as the Kamidaki Line; the result was a Tateyama Line running from Terada to Senjugahara. On 1 July 1970 Senjugahara Station was renamed Tateyama Station (and the old Tateyama-machi station became Gohyakkoku). Centralised traffic control (CTC) was commissioned on the line on 8 July 1976.

The Tateyama Line remains Chitetsu's gateway to the high mountains, but the upper section has come under pressure. Awasuno Station closed on 22 May 1981, and one-man operation began in 1997 with the closure of Kami-Yokoe. In 2025 the railway moved to scale back winter operation on the upper Iwakuraji–Tateyama section to morning and evening trains only, and agreement was reached to begin a rebuilding (reconstruction) project for that section from fiscal 2027 to keep it in service.

• 191325 June: the Tateyama Light Railway opens a 762 mm gauge line between Namerikawa and Gohyakkoku — the network's oldest section, now part of the Toyama Chihō Railway Main Line rather than the Tateyama Line.
• 1917The Tateyama Light Railway is renamed the Tateyama Railway.
• 192119 March: the Tateyama Railway opens Gohyakkoku to a first-generation 'Tateyama' station near present-day Iwakuraji (distinct from today's Tateyama Station) — the start of the Tateyama Line proper.
• 192111 October: the Toyama Prefectural Railway opens the Iwakuraji–Yokoe section up the valley (Yokoe later became Kami-Yokoe, closed 1997).
• 1927The prefectural Iwakuraji–Chigaki section is electrified at 600 V DC.
• 19316 April: the Tateyama Railway is absorbed by the Toyama Electric Railway. 15 August: the Toyama Electric Railway opens Terada–Gohyakkoku at 1,067 mm gauge, electrified at 1,500 V DC.
• 193618 August: the Gohyakkoku–Iwakuraji section is regauged to 1,067 mm and electrified at 1,500 V DC.
• 1937The prefectural section is raised to 1,500 V DC; the line is extended further up the valley (Chigaki–Awasuno opens 1 October), toward Arimineguchi.
• 19431 January: the prefectural railway and the railway lines of Nippon Hassōden are transferred to the newly created Toyama Chihō Railway, consolidating the segments under one company.
• 19541 August: the Awasuno–(provisional) Tateyama section opens. The Omi–Awasuno stretch is transferred to the Tateyama Development Railway the same year.
• 19551 July: the (provisional) Tateyama–Senjugahara section opens; Senjugahara is the present site of Tateyama Station.
• 19691 April: a network reorganisation incorporates the former Gohyakkoku Line into the Tateyama Line and splits off the Fujikoshi Line (Inarimachi–Minami-Toyama) and the Kamidaki Line (Minami-Toyama–Iwakuraji); the Tateyama Line now runs Terada–Senjugahara.
• 19701 July: Senjugahara Station is renamed Tateyama Station (and the former Tateyama-machi station becomes Gohyakkoku).
• 19768 July: centralised traffic control (CTC) is commissioned on the line.
• 198122 May: Awasuno Station closes.
• 19971 April: Kami-Yokoe Station closes and one-man operation begins on the line.
• 2025Winter operation on the upper Iwakuraji–Tateyama section is cut back to morning and evening trains only; agreement is reached to begin a rebuilding (reconstruction) project for that section from fiscal 2027 to keep it in service.