The is the name given to a rapid train service in Greater Tokyo, operating between in Chiyoda, and in Hachioji by the East Japan Railway Company (JR East). Some trains extend west beyond Takao to Ōtsuki in neighboring Yamanashi Prefecture. Other trains travel onward towards Ōme via the Ōme Line. It has been operating continuously in some form since April 1889 from its origins as part of the Kōbu Railway.
Chūō Line (Rapid) trains often rank among the most overcrowded in the Tokyo metropolitan area. It is the only mainline service to operate directly into the core of Tokyo without traveling through another company's tracks or customers having to change trains, and serves highly desirable communities in western Tokyo.
For station numbering, it is identified with the code JC. It is colored orange vermillion on railway maps, and E233-0 series trains assigned to the service have stripes with this color.
History Early history
Most of the route of the Chūō Line (Rapid) was built by the during the Meiji era and entered service in two phases as the Kōbu Line. The first was between Tachikawa and Shinjuku, opening on 11 April 1889. Trains took one hour to travel between those two points and only went as fast as 30 km/h (18.64 mph). The second section between Tachikawa and Hachioji opened later on 11 August. Around the time of opening, there were only four round trips per day, and only one of them traveled the full route between Hachioji and Shinjuku. Additionally, as most of west Tokyo was not yet developed or populated, stations were only located at Nakano, Sakai (now Musashi-Sakai), Kokubunji, and Tachikawa. This was expanded to six round trips with an extension to Iidamachi (near today's Iidabashi) in April 1895.
In response to high ridership, the line was electrified in August 1904 between Nakano and Iidamachi, becoming the first rapid electric railway in Tokyo and electric powered De-968 cars were brought into service. Service was extended to Ochanomizu on 31 December 1904. Kōbu Railway was later acquired by Japanese Government Railways (JGR), and was nationalized on 1 October 1906. At that time, the line adopted its current name, the Chūō Line.
In the 1910s, service was extended further eastwards into central Tokyo, first to Manseibashi in April 1912, and then to the current Tōkyō terminus in March 1919.
By 1930, the line had been electrified between Tōkyō to the east, and Asakawa (now Takao) to the west. In 1933, two additional tracks were added to the existing double-tracked section between Ochanomizu and Iidamachi stations to complete the four-track line between Ochanomizu and Nakano. This allowed the introduction of , a precursor to current rapid service, on 15 September. These trains only stopped at Tōkyō, Kanda, Manseibashi, Ochanomizu, Yotsuya, Shinjuku, and Nakano. Express service only operated during peak hours on weekdays.
Post-war
After World War II, JGR became Japanese National Railways (JNR). Areas of west Tokyo experienced large population growth during the post-war boom, and in turn resulted in very crowded trains, some operating at 300% above full capacity.
JNR 101 Series trains were introduced starting in December 1957 with a prototype unit.Masa Shindo "The Story of Chuo Rapid 101 Series" "Railway Pictorial" April 2013 issue, p. 73 Production trains were delivered to Mitaka Depot and entered service a year later. These electric trains had four double-leafed doors per side, featured quicker acceleration, and were 10 cars long, ideally accommodating as much as 1,400 passengers per train. They were colored orange vermillion (officially JNR Vermillion No. 1), which became the trademark color for the Chūō Line and all its future rolling stock.
In November 1959, all-day express service was introduced on weekdays.
On 17 March 1961, the Chūō Line express trains were rebranded as . This was done to reduce confusion, as a limited express service, the Azusa, was being extended to Shinjuku, but required higher fares than the conventional rapid trains on the line. Weekend and holiday rapid service commenced in April 1966, though some trains during the first and last hours of service continue to make all local stops. On 3 July 1967, a Special Rapid service variant was introduced, stopping at fewer stations than normal Rapid service. These trains generally operated between Tōkyō and Takao or Ōme, and made all normal Rapid service stops east of Nakano. Between Nakano and Tachikawa, these trains operated as a super-express service, only stopping (from east to west) at Mitaka, Kokubunji, and Tachikawa. Kokubunji was skipped on these trains until 1993.
Prototype 201 series trains began operating on 20 August 1979, with full service starting in August 1981, replacing the 101 series cars.
By 1987, Japanese National Railways had incurred a large amount of debt – ¥27 million. It was broken up and privatized into seven separate companies within the Japan Railways Group. The Chūō Line (Rapid) and other lines in the Kantō region fell under control of the East Japan Railway Company, or JR East.
In December 1988, another variant of rapid service began operation, the Commuter Rapid. These trains only operate outbound from Tōkyō during the afternoon peak and continue through the mid-evening. Between Nakano and Tachikawa, these trains only stop at Ogikubo, Kichijōji, Mitaka, and Kokubunji.
In April 1993, another Rapid variant began service, the Commuter Special Rapid. These trains only operate towards Tōkyō during the morning rush hour. By this point, direct Rapid service trains were also operating to and from Ōtsuki.
2000s to the present
The 2000s brought on a major project to grade separate the line between Mitaka and Tachikawa at the cost of ¥180 billion. There were multiple grade crossings along the right-of-way, and as a result of frequent train service, gates were often closed. This led to high levels of traffic congestion, accidents, and a feeling amongst nearby residents of being disconnected from one another. The work along this 9 km (5.59 mi) section was done in phases, two tracks at a time starting in 1999, with trains using the two remaining tracks. The project was substantially completed in November 2010.
Women-only cars were introduced on 5 September 2005, they were offered during various periods in the past, even during the early days of the Chūō Line. Some iterations of this policy also allowed children of any gender to ride in these cars. On Chūō Line (Rapid) trains, this is car number #1, the first car on all trains towards Tōkyō. The policy is only in effect during the height of the morning peak on weekdays.
On 26 December 2006, E233 series trains entered service, and remains the current rolling stock on the line. 688 cars were initially ordered to replace the older 201 series trains, which operated until 14 October 2010.JR East news release: "「さよなら中央線201系」キャンペーン＜第2弾＞を開催します" (25 February 2010). Retrieved 17 June 2010. (in Japanese) The E233s were built with universal design in mind, and JR East surveyed customers to gather further input on features to include such as air purification, and lower luggage racks in women-only cars. They also have backup internal systems in case of failure, reducing potential service disruptions.
In 2016, station numbering was introduced with stations being assigned numbers between JC01 (Tōkyō) and JC24 (Takao). Stations on the Ōme and Itsukaichi lines, where some trains operate as through services, are also identified with JC station codes.
JR East planned to introduce green cars on both the Chūō Line (Rapid) and Ōme Line in spring 2025. To do so, two newly built bilevel green cars would be added to each 10-car and 6-car E233 series EMU set, forming 12-car and 8-car sets respectively. In addition, toilets were also installed in each trainset. Work was done to lengthen station platforms and depot facilities to handle longer trains. Two sets of 209-1000 series EMUs were placed into Chūō Line (Rapid) service from March 2019 to October 2024 as there were a temporary shortage of E233 series trains because of this work.
On 14 March 2020, the remaining few late evening and early morning local trains were converted to rapid service.
Through services to some lines in the Tama region were discontinued in the 2020s. Through services to the Hachikō Line and Itsukaichi Line ended on 11 March 2022 and the Holiday Rapid Akigawa (a holiday and weekend through service) was discontinued about a year later on 18 March 2023.
JR East announced the introduction of Green Car equipped trains from 13 October 2024 on a trial basis without additional fares. Full deployment (with fares) commenced in early 2025. It was reported in October 2025 that some passengers were using green cars without paying the proper step-up fare.
Issues
Suicides and personal injury accidents
The Chūō Main Line and by extension, the Chūō Line (Rapid) service has a high rate of personal injury accidents. By 2000, the Chūō Line had the highest reported number of personal injury accidents (including suicides) in the JR East network. This morbid lore has also been represented in fictional works; the opening scene in the 2001 film, Suicide Club depicts the mass suicide of schoolgirls who jump in front of an oncoming Chūō Line train.
Between January 2010 and September 2025, there have been 483 of these incidents along the Chūō Line. Various causes have been discussed for this, including the lack of platform screen doors at most stations, the high rate of speed which trains travel at, and that JR East reportedly charges the lowest fees for railway damages to the families of those deceased (railway operators in Japan often seek financial compensation after personal injury accidents that result in costs to the company).
In response to this, JR East has made efforts to reduce the number of these incidents overall, including the installation of improved fencing at stations, reducing blind spots, adding blue lighting and mirrors at the ends of platforms, increasing lighting throughout stations, and having former staff patrol stations looking for those potentially in need. There are also plans to install platform screen doors at stations along the Chūō Line by fiscal year 2032.
Crowding
The Chūō Line serves a large portion of West Tokyo, and as a result, has historically experienced severe crowding. After World War II, a lack of space for further development of housing in central Tokyo led to a rapid build-up in formerly quiet areas, especially to the west. In turn, ridership on the Chūō Line also increased, and became a key corridor along these rapidly growing communities. Train lengths were increased to 10 cars by 1956.
In some cases, trains were operating at about 300% capacity, or three times the ridership that they were designed to safely carry. Conditions were so dangerous, the Chūō Line began to carry the nickname of the Murder Line. Beginning in the 1960s, JNR began making serious efforts to address overcrowding as part of its Commuting Five Directions Operation plan. The Chūō Main Line was quadrupled tracked and grade separated between Nakano and Ogikubo in April 1966, and later westward from Ogikubo to Mitaka in April 1969. This allowed the extension of Chūō-Sōbu Line service to Mitaka from its then terminus at Nakano to provide additional local service. In addition, the Tozai subway line was extended to Nakano in March 1966, and through-running service on the Chūō-Sōbu Line to Mitaka was introduced one month later, the first ever through-run service by JNR. JNR's efforts began to pay dividends: in 1965, crowding levels were at 266% above capacity, down from earlier post-war counts.