Okinawa, Japan declares SkyTrain technology for 69km urban and intercity railway

Okinawa Railway System - Urban elevated railway station concept

As you may recall (or not, since I have yet to actually discuss anything Japan-related on this blog!), I departed Metro Vancouver in September of this year to pursue a scholarship-supported abroad studies program in Kyushu, Japan. My studies include a transportation research component – and through this, I initially received word that Okinawa would use linear motor cars on its inaugural island railway – a.k.a. “SkyTrain technology”.

As of this week, a number of online articles in Japanese have now surfaced, revealing project details and effectively confirming SkyTrain technology for Okinawa’s first major rapid transit line.

News release: 知事選で高まる気運 リニアモーターを使った沖縄の「普通鉄道」建設構想とは (English: Election momentum growing: plan outlined for Okinawa’s linear motor railway)
Translated (Google): [LINK]

This means that linear motors and reaction rails (locally termed in Vancouver as “SkyTrain technology”) will be used to propel trains on the island. Japan is one of the world countries that has recognized the benefits of SkyTrain technology, with 7 lines running or already under construction in 6 cities. Okinawa’s railway will be the 8th such line in Japan, and the 19th such line in the world.

See also: List of Linear Induction Motor Rapid Transit Systems

The news release linked above emphasizes that every candidate for prefectural governor (there is an election coming up in Okinawa!) is supporting the proposed rapid transit line. This is because the line will be 30% cheaper to ride end-to-end than the current express bus service, due to efficiencies for the island’s transit operator. It is expected to cut travel time across the island in half, to 58 minutes from the current 1 hour and 45 minutes by rapid express bus.

There will be two primary segments. The 20km segment between Okinawa City and Naha Airport will feature an urban metro-style service. Trains will initially run every 5 minutes during peak hours, and every 12 minutes off-peak. The 49km segment between Okinawa City and Naga City will be the world’s first intercity railway using SkyTrain technology. Trains will initially arrive every 15 minutes during peak hours and every 20 minutes off-peak.

Map of proposed 69km SkyTrain-type railway in Okinawa
Map of Okinawa’s 69km SkyTrain technology railway

The line will initially use 4-car trains, with shorter 12m long cars – similar to Vancouver SkyTrain’s Mark I vehicles. They will be low-height vehicles capable of running through smaller tunnels.

最高速度は100km/hが目標とされており、長さ12mの車両の4両編成が考えられています。1両あたりの長さが約15.7mである長堀鶴見緑地線の車両が、4両編成で定員が380人なので、12m×4両では単純計算で290人程度の定員があることになります

English: Trains will have a maximum speed of 100km/h, and the government has considered using 12m length cars. For comparison, trains on Osaka’s Nagahori Tsurumi-Ryokuchi line are 15.7m long. Those trains carry 380 people, so we imply that Okinawa’s trains will carry 290 people between the 4 cars.

In order to navigate the island’s challenging terrain, 70% of the proposed line will be in a tunnel, which means the linear motor trains – which have lower train heights and require smaller tunnel diameters – will save the local government billions of dollars in tunneling costs. A standard rotary propulsion railway would have also likely required more tunnels, given linear motor vehicles are capable of handling steeper slopes at higher speeds, avoiding the need for tunnels and landscaping in certain segments.

Case study

With further searching, I was able to uncover a case study document that included conceptual art for the proposed rail line:

LINK: 新たな公共交通システム導入促進検討業務 – 報 告 書 – 概 要 版 – 沖 縄 県 (English: New public transit system promotional business case – Executive Summary – Okinawa Prefecture)

According to the study, the SkyTrain-type rapid transit line was initially compared on a level playing field with a variety of other transit options – including Tram-Train – a form of ground-level Light Rail Transit (LRT), and Bus Rapid Transit (BRT) – and won against these options, found to be the most worthwhile investment as it would generate the most travel time benefits for local citizens.

The linear motor transit systems examined in the study included the Bombardier ART (SkyTrain) systems in New York and Beijing.

About Okinawa

A map of Okinawa prefecture - from Wikimedia Commons, license CC-BY-SA
A map of Okinawa prefecture – from Wikimedia Commons, license CC-BY-SA

Okinawa, a well-populated and internationally well-known island south of the 4 main Japanese islands, is contrary to the rest of the country in that it has yet to see any serious developments in rail transit. There is a 12.8km monorail, called Yui Rail, in the main city (Naha), but that is it – the rest of the population must take buses or drive automobiles to travel longer distances.

The new railway will significantly improve transit travel times and create a new option to combat rising congestion levels on the Okinawa Expressway, a major toll road crossing the island. The entire railway will be 69km long, which will immediately make it the third longest SkyTrain-technology rail system in the world upon completion. Vancouver’s SkyTrain system (which will grow with the completion of the Evergreen Line) and Guangzhou, China (where three SkyTrain technology lines cover 100km of track) are the only longer systems.