Tsukuba Express

The project grew out of a long planning history. As early as 1978 Ibaraki Prefecture floated the idea of a "Second Jōban Line" to relieve congestion, and in 1985 the construction of the Jōban New Line was written into Report No. 7 of the Transport Policy Council, the document that frames Tokyo-area rail planning. A decisive enabling step came in 1989 with the enactment of the Special Measures Law on the Integrated Promotion of Residential Land Development and Railway Construction in Major Metropolitan Areas — the "Takutetsu Law" — which tied building the railway to coordinated housing development along its corridor and so secured land and funding.

To carry out the scheme, the Metropolitan Intercity Railway Company was founded on 15 March 1991, with investment from the four prefectures and the dozen municipalities the line would cross. The national basic plan under the Takutetsu Law was approved later that year, and the company obtained its Type-1 railway business licence in 1992. The original concept had called for a line from Tokyo Station to Moriya, but the expense of reaching Tokyo Station forced the planners to begin the line at Akihabara instead.

Construction began in earnest with a groundbreaking ceremony at Akihabara on 28 October 1994. The line was bored and elevated through dense suburbs over the following decade, with roughly a quarter of the route in tunnel and most of the remainder on viaduct or in cutting so as to avoid level crossings entirely. In February 2001 the operator announced the public service name that would replace the planning title: "Tsukuba Express."

The Akihabara–Tsukuba line opened on 24 August 2005, cutting the journey between central Tokyo and the science city of Tsukuba to about three-quarters of an hour. Because the route crosses the geomagnetic observatory zone at Ishioka, the line could not use direct current throughout: it is electrified at 1,500 V DC south of Moriya and at 20 kV 50 Hz AC north of it, so that trains running the full length must be dual-system. The DC-only TX-1000 series works the southern section, while the dual-voltage TX-2000 series — joined from 14 March 2020 by the newer TX-3000 series — operates over the whole line.

Ridership grew quickly and strongly. The line carried an average of about 150,700 passengers a day in its first year; cumulative ridership passed 100 million in March 2007, and the company's target of 270,000 passengers a day was reached in April 2009, years ahead of schedule. Patronage climbed to a peak of around 395,400 a day in fiscal 2019 before the COVID-19 pandemic cut it to about 277,900 in fiscal 2020; it subsequently recovered and surpassed the earlier peak, reaching roughly 403,000 a day in fiscal 2024.

That sustained growth, and the heavy morning crowding it produced, pushed the operator to plan a major capacity upgrade. On 31 May 2019 the company formally decided to lengthen its trains from six cars to eight. The work is expected to take more than a decade, with eight-car operation due to begin in the first half of the 2030s; it is projected to raise the capacity of each train by about 30 percent and to bring the morning peak congestion rate down to 150 percent or below.

• 1978Ibaraki Prefecture floats the idea of a 'Second Jōban Line' to relieve congestion on the Jōban Line corridor.
• 198511 July: construction of the Jōban New Line is written into Report No. 7 of the Transport Policy Council.
• 1989June: the 'Takutetsu Law' (Special Measures Law on the Integrated Promotion of Residential Land Development and Railway Construction in Major Metropolitan Areas) is enacted, tying the railway to coordinated housing development.
• 199115 March: the Metropolitan Intercity Railway Company is founded to build the line, with investment from the four prefectures and the municipalities along the route; the basic plan under the Takutetsu Law is approved on 23 October.
• 1992January: the company obtains its Type-1 railway business licence. The southern terminus had been moved from Tokyo Station to Akihabara because reaching Tokyo Station proved too costly.
• 199428 October: a groundbreaking ceremony is held at Akihabara and full-scale construction begins.
• 20012 February: the public service name 'Tsukuba Express' is announced, replacing the planning name 'Jōban New Line'.
• 200524 August: the Akihabara–Tsukuba line opens — 58.3 km, 20 stations, fully grade-separated, up to 130 km/h, electrified 1,500 V DC south of Moriya and 20 kV 50 Hz AC north of it; first-year ridership averages about 150,700 a day.
• 2007March: cumulative ridership passes 100 million.
• 2009April: the company's target of 270,000 passengers a day is reached, years ahead of schedule.
• 201111 March: services are suspended line-wide after the Great East Japan Earthquake, then resumed in stages.
• 2019Ridership peaks at about 395,400 passengers a day in fiscal 2019. On 31 May the company formally decides to lengthen trains from six cars to eight, with eight-car operation due in the first half of the 2030s.
• 202014 March: the new TX-3000 series enters service. Ridership falls to about 277,900 a day in fiscal 2020 owing to the COVID-19 pandemic.
• 2024Ridership recovers past its earlier peak to roughly 403,000 passengers a day in fiscal 2024.