Shikoku Shinkansen () is a general term for two planned Shinkansen routes connecting Honshu, Kyushu and Shikoku. There are two planned routes: the Shikoku Shinkansen and the Trans-Shikoku Shinkansen. Together with the Chūō Shinkansen and Trans-Kyushu Shinkansen, it is a high-speed railway plan for Western Japan that constitutes the Pacific New National Axis in the "Grand Design for the National Land in the 21st Century". Although it is not included in the planned Shinkansen, since 2011, in response to the results of a basic survey, there has been active promotion to upgrade it to a planned development plan. It is expected that the extension of the Linear Chūō Shinkansen to Shin-Osaka Station will be realized as early as 2037, and a "super mega-region" will be formed by integrating the three major metropolitan areas. The Shikoku Shinkansen Development Promotion Association is aiming to open the Shikoku Shinkansen in 2037 to coincide with this. After the opening of the Chūō Shinkansen, travel times between Tokyo and Tokushima, Takamatsu, Matsuyama, and Kochi will all be in the two-hour range, with the exception of transfers at Shin-Osaka.
Since fiscal 2017, the Ministry of Land, Infrastructure, Transport and Tourism has been conducting a survey on the "Form of Trunk Railway Network, etc." to collect basic data on transport density and time distance between major cities, research into efficient Shinkansen development methods including the construction of single-track Shinkansen lines, methods for increasing the speed of conventional lines, and methods for connecting with existing trunk railways.
Shikoku Railway Company (JR Shikoku), the operator of the Shikoku Shinkansen, has included the introduction of the Shinkansen in its medium- to long-term management plans leading up to 2030, "Long-term Management Vision 2030," and "Medium-term Management Plan 2025".
Overview
Shikoku Shinkansen The Shikoku Shinkansen will start in Osaka, pass through Tokushima, Takamatsu and Matsuyama, and end in Oita, on the eastern tip of Kyushu. The total length between Osaka and Oita is about 480 km. It is planned to set up connecting facilities near Shirakawa Pass, west of Shin -Kobe Station on the Sanyo Shinkansen, and near Yoshinari Station on the Kotoku Main Line.
It was envisaged that the Awaji Island would be passed between Honshu and Shikoku, and for this reason the Onaruto Bridge was designed as a combined road and railway bridge. However, the Akashi Kaikyo Bridge, which was later constructed, was changed to a road-only bridge, and it became necessary to excavate a separate undersea tunnel through the Akashi Strait or Kitan Strait to allow railway traffic. The Japan Railway Construction, Transport and Technology Agency conducted a survey of the topography and geology of both straits, but budget execution was suspended in fiscal 2008. In addition, a bridge or undersea tunnel (Hoyo Strait Route) is required over the Hoyo Strait to reach Ōita City from Shikoku. The estimated project cost of the Shikoku Shinkansen (Case 1), which requires the construction of a bridge or undersea tunnel over the Akashi Strait, Kitan Strait or Hoyo Strait, is estimated at 4.02 trillion yen.
The Chūō Shinkansen is scheduled to open in Osaka City, where it starts, in 2037. If the Shikoku Shinkansen is constructed as an extension of the Chūō Shinkansen and connected to the Kyushu Shinkansen, which has a large population along the line, via the Hoyo Undersea Tunnel, Tokyo and Kyushu could be connected in less than two and a half hours, and a considerable demand for the Shikoku Shinkansen itself is expected. There is also a plan to build the Shikoku Shinkansen using the linear method, as it could serve as a backup route for the Tokaido-Sanyo Shinkansen and serve as the main transportation system for the second national axis, the New Pacific National Axis.
Route plan
Early documents from the Shikoku Railway High Speed Liaison Committee and other sources showed a proposed route and station locations, with the line connecting to the Kyushu Shinkansen at Saganoseki in Oita City and allowing trains to continue to Hakata, Kokura, Ōita, Miyazaki and Kagoshima-Chūō stations.
Shin-Ōsaka Station - Tennōji Station - Sennan Station - Kita-Wakayama Station - Kitan Strait - Awajishima Station - Ōnaruto Bridge - Shin-Naruto Station - Shin-Takamatsu Station - Kotohira Station - Shikoku Chuo Station - Iyo-Komatsu Station - Shin-Matsuyama Station - Ozu Station - Shin-Yawatahama Station - Misaki Station - Bungo Strait - Saganoseki Station - Ōita Station A case study conducted in the "2019 Survey on the Status of Trunk Railway Networks, etc." analyzed the construction of a single-track 300 km line with branches and junctions along the way. The route map in the case study does not specify "Shikoku Shinkansen" or "Shikoku Trans-Shikoku Shinkansen," but the content is consistent with the construction plan for the 302 km line in Shikoku. The route map for the Shikoku Shinkansen does not include the names and locations of each station, but the structure of each station and the distance between stations can be read.
Tracks...‖: double track section, |: single track section, ◇・◆: train interchange possible (◆ is a switchback station), ∨: below this point is single track, ∧: below this point is double track
Station Name Station Structure Distance From Station A (KM) Type Location (TBD) Remarks K Terminal station (2 platforms, 4 tracks) 130 J Intermediate station (2 platforms, 2 tracks) 100 I Major stations (2 platforms, 4 tracks) 70 C Branch station (2 platforms, 4 tracks) 50 Trains running between Station A and Station I/K switch back here D Intermediate station (2 platforms, 2 tracks) 75 E Branch station (2 platforms, 4 tracks) 95 Trains running between Station A and Station L branch off here. F Intermediate station (2 platforms, 2 tracks) 120 G Intermediate station (2 platforms, 2 tracks) 130 In the case of a single track, a signal box is installed to allow for passing of trains. H Terminal station (2 platforms, 4 tracks) 175
Trans-Shikoku Shinkansen The Trans-Shikoku Shinkansen, which starts in Okayama and runs towards Kōchi, was designed and planned on November 15, 1973. The Great Seto Bridge and its sections before and after it were built to Shinkansen standards, but because no government funding was provided in 2008, and the national preliminary surveys required for construction were not carried out. The planned sites for the Shinkansen platforms at Kojima Station and Utazu Station are large plazas in front of the stations.
Route plan
The route listed in early documents from the Shikoku Railway High Speed Liaison Committee and other sources does not include the section from Okayama City across the Seto Ohashi Bridge to Shikokuchūō City, but instead shows a branch line that branches off from the Shikoku Shinkansen at Shikokuchūō City and continues to Kochi City. The intermediate station is listed as "Motoyama Station," which suggests that there was a plan to build a station in Motoyama Town in the Reihoku region of Kochi Prefecture.
Shikoku Chuo Station - Motoyama Station - Kochi Station The case study conducted in the "2019 Survey on the Status of Trunk Railway Networks, etc." includes a route map for the Shikoku Transit Shinkansen. Although the names and locations of each station are not written, the structure of each station and the distance between stations can be seen.
Tracks...‖: double track section, |: single track section, ◇・◆: train interchange possible (◆ is a switchback station), ∨: below this point is single track, ∧: below this point is double track
Station Name Station Structure Distance From Station A (KM) Type Location (TBD) Remarks A Branch station (2 platforms, 4 tracks) 0 Direct service to major cities using existing Shinkansen lines 5 Junction with existing Shinkansen lines B Intermediate station (2 platforms, 2 tracks) 30 C Branch station (2 platforms, 4 tracks) 50 Trains running between Station A and Station I/K switch back here D Intermediate station (2 platforms, 2 tracks) 75 E Branch station (2 platforms, 4 tracks) 95 Trains running between Station A and Station L branch off here. In the case of a single track, a signal box is installed to allow for passing of trains. L Terminal station (2 platforms, 4 tracks) 145
Developments in the 2010s At a press conference on May 25, 2010, when he was confirmed as president of JR Shikoku, Izumi Masafumi stated his desire to increase the speed of conventional railway lines in order to compete with private automobiles, saying, "We may not go as far as the Shinkansen, but unless we can connect cities at around 200 kilometers per hour, there will be no point in having them here."
It was later reported that Chairman Kiyohiro Matsuda and President Izumi mentioned speeding up the line, including a short-circuit on the Yosan Line at the base of the Takanawa Peninsula. President Izumi said the cost of speeding up the line (including the Dosan and Kotoku Lines) would be 150 billion yen, and that they were seeking government support.
The "Shikoku Railway Network Discussion Group", which was established in 2010 by representatives of the Shikoku economy and local governments to discuss railways in Shikoku, reported at its final meeting on July 27, 2011 that it would clearly state in its proposal to be submitted to the national government that the Shinkansen would be introduced to increase speed, and that a super express system would be adopted by improving the tracks of existing railways (see the external link below for details of the proposal).
In its five-year medium-term management plan announced in April 2012, JR Shikoku stated that it would “continue to conduct research to determine the business feasibility of the Shinkansen”.