Tama Toshi Monorail Line

The monorail grew out of metropolitan transport planning that long predated construction. From 1979 the Tokyo Metropolitan Government carried out basic surveys of an urban monorail for the Tama district, and in 1981 a conceptual network of roughly 93 kilometres was put forward; in September 1982 the Japan Monorail Association published its own draft monorail plan for the area. The Tama region was being transformed by the growth of Tama New Town, the huge planned suburb spread across the hills of the south-western metropolis, and a north-south backbone was sought to tie its scattered districts into the existing east-west commuter network.

The project crystallised in the late 1980s. On 26 December 1987 a track licence under the Tramways Act was obtained for the whole Kamikitadai-to-Tama-Center route, and an urban-planning decision followed in September 1989. Construction was authorised in stages: the Kamikitadai-to-Tachikawa-Kita section was approved in June 1990, with a groundbreaking ceremony on 26 November 1990 and work beginning that December, while the Tachikawa-Kita-to-Tama-Center section was approved in September 1991 and started in November of the same year.

After several years of building the elevated guideway across the hilly terrain, main-line test running began on 19 December 1997. The first stage opened to passengers on 27 November 1998, when trains began running between Kamikitadai and Tachikawa-Kita, linking the northern Tama suburbs to the regional hub of Tachikawa and its busy JR interchange.

The second stage completed the line. On 10 January 2000 the section between Tachikawa-Kita and Tama-Center opened, extending the monorail south across the Tama Hills to the heart of Tama New Town and bringing the full route into service at its present length of 16.0 kilometres and 19 stations. From Tachikawa the line now ran continuously to Tama-Center, where it met the Odakyū Tama Line and the Keiō Sagamihara Line, completing the north-south spine that planners had envisaged two decades earlier.

The new monorail proved popular. Cumulative ridership passed 100 million on 15 November 2002, less than three years after the full line opened, reached 500 million on 27 June 2012, and surpassed 700 million on 28 August 2016, figures that reflected its role as a daily artery for commuters and students in the western suburbs. In 2018 the operator marked the line's twentieth anniversary with a commemorative period, and on 23 March 2019 it carried out its first comprehensive timetable revision since opening.

From the outset the line was conceived as part of a larger network, and extensions have been pursued throughout its life. The most advanced is a northward extension of about seven kilometres from Kamikitadai to Hakonegasaki, with seven new stations; a track licence under the Tramways Act for this section was obtained on 9 May 2025, following an application to the Minister of Land, Infrastructure, Transport and Tourism on 23 July 2024, and the company is advancing procedures toward construction with an opening targeted for the mid-2030s. Other proposals have fared differently: a southern extension from Tama-Center toward Hachiōji was abandoned in December 2016 on topographical and technical grounds, while a separate extension from Tama-Center toward Machida remained without a fixed route as of January 2022.

Today the Tama Toshi Monorail Line is a fixture of the western Tokyo landscape, its slender concrete beam curving above the streets between Higashiyamato and the Tama New Town hills. As the only railway running north-south through the centre of the Tama district, it remains a vital cross-link in a commuter region otherwise built around east-west trunk lines, with its long-planned extension toward Hakonegasaki now finally moving from drawing board to reality.

• 1979The Tokyo Metropolitan Government carries out basic survey work on an urban monorail for the Tama district.
• 1981A conceptual monorail network of roughly 93 kilometres for the Tama region is put forward.
• 1982September: the Japan Monorail Association publishes a draft monorail plan for the area.
• 198726 December: a track licence under the Tramways Act is obtained for the Kamikitadai-to-Tama-Center route.
• 1989September: the urban-planning decision for the line is made.
• 1990Construction of the Kamikitadai-to-Tachikawa-Kita section is authorised in June; a groundbreaking ceremony is held on 26 November and work begins in December.
• 1991The Tachikawa-Kita-to-Tama-Center section is authorised in September and construction begins in November.
• 199719 December: main-line test running begins.
• 199827 November: the first stage between Kamikitadai and Tachikawa-Kita opens to passengers.
• 200010 January: the Tachikawa-Kita-to-Tama-Center section opens, completing the line at 16.0 km and 19 stations.
• 200215 November: cumulative ridership passes 100 million.
• 201227 June: cumulative ridership reaches 500 million.
• 201628 August: cumulative ridership surpasses 700 million. (December: the proposed southern extension toward Hachiōji is abandoned.)
• 201923 March: the line's first comprehensive timetable revision since opening is carried out.
• 202423 July: the company applies to the Minister of Land, Infrastructure, Transport and Tourism for a track licence for the Kamikitadai-to-Hakonegasaki extension.
• 20259 May: a track licence under the Tramways Act is obtained for the Kamikitadai-to-Hakonegasaki extension (about 7 km, seven stations), targeting an opening in the mid-2030s.