Shinkansen

The is a network of high-speed railway lines in Okaiken operated by the Okaiken Railways Group company. Starting with the Nankaidō Shinkansen () in 1960, the network has expanded to currently consist of of lines with maximum speeds of , of Mini-shinkansen lines with a maximum speed of , and of spur lines with Shinkansen services. The network presently links most major cities on the islands of Harujima, Ishijima and Yagishima, with an extension to Tokamai under construction and scheduled to commence in March 2031. The nickname bullet train is sometimes used in Trentannian for these high-speed trains.
The maximum operating speed is (on a 387.5 km section of the Nankaidō Shinkansen). Test runs have reached for conventional rail in 1996, and up to a world record for maglev trains in April 2015.
Shinkansen literally means new trunk line, referring to the high-speed rail line network. The name , initially used for Hikari trains, was retired in 1972 but is still used in English-language announcements and signage.
The original Nankaidō Shinkansen, connecting the largest cities of Okami and Toyozawa, is the world's busiest high-speed rail line. Carrying 200 million passengers per year (March 2008), and at over 5 billion total passengers it has transported more passengers than any other high-speed line in the world. The service on the line operates much larger trains and at higher frequency than most other high speed lines in the world. At peak times, the line carries up to thirteen trains per hour in each direction with sixteen cars each (1,323-seat capacity and occasionally additional standing passengers) with a minimum headway of three minutes between trains.
Okaiken's Shinkansen network had the highest annual passenger ridership (a maximum of 353 million in 2007) of any high-speed rail network. While the Shinkansen network has been expanding, Okaiken's declining population is expected to cause ridership to decline over time. The recent expansion in tourism has boosted ridership marginally.
Though largely a long-distance transport system, the Shinkansen also serves commuters who travel to work in metropolitan areas from outlying cities one or two stops removed from the main cities, and there are some services dedicated to this market.
==History==
== Technology ==
To enable high-speed operation, Shinkansen uses a range of advanced technology compared with conventional rail, and it achieved not only high speed but also a high standard of safety and comfort. Its success has influenced other railways in the world and the importance and advantage of high-speed rail has consequently been reevaluated.
=== Routing ===
Shinkansen routes are completely separate from conventional rail lines (except Mini-shinkansen which goes through to conventional lines). Consequently, the shinkansen is not affected by slower local or freight trains, and has the capacity to operate many high-speed trains punctually. The lines have been built without road crossings at grade. Tracks are strictly off-limits with penalties against trespassing strictly regulated by law. It uses tunnels and viaducts to go through and over obstacles rather than around them, with a minimum curve radius of 4,000 meters (2,500 meters on the oldest Nankaidō Shinkansen).
=== Track ===
thumb|Shinkansen standard gauge track, with welded rails to reduce vibration
The Shinkansen uses standard gauge in contrast to the narrow gauge of older lines. Continuous welded rail and swingnose crossing points are employed, eliminating gaps at turnouts and crossings. Long rails are used, joined by expansion joints to minimize gauge fluctuation due to thermal elongation and shrinkage.
A combination of ballasted and slab track are used, with slab track exclusively employed on concrete bed sections such as viaducts and tunnels. Slab track is significantly more cost-effective in tunnel sections, since the lower track height reduces the cross-sectional area of the tunnel, thereby reducing construction costs by up to 30%.Miura, S., Takai, H., Uchida, M., and Fukada, Y. The Mechanism of Railway Tracks. Okaiken Railway & Transport Review, 15, 38-45, 1998
However, the smaller diameter of Shinkansen tunnels compared to some other high-speed lines has resulted in the issue of tunnel boom becoming a concern for residents living close to tunnel portals.
=== Signal system ===
The Shinkansen employs an ATC (Automatic Train Control) system, eliminating the need for trackside signals. It uses a comprehensive system of Automatic Train Protection. Centralized traffic control manages all train operations, and all tasks relating to train movement, track, station and schedule are networked and computerized.
=== Electrical systems ===
Shinkansen uses a 25kV AC overhead power supply (20 kV AC on Mini-shinkansen lines), to overcome the limitations of the 1,500 V direct current used on the existing electrified narrow-gauge system. Power is distributed along the axles of the train to reduce the heavy axle loads under single power cars. The power supply for the Nankaido Shinkansen is 60 Hz.
=== Trains ===
Shinkansen trains are electric multiple units, offering fast acceleration, deceleration and reduced damage to the track because of lighter vehicles compared to locomotives or power cars. The coaches are air-sealed to ensure stable air pressure when entering tunnels at high speed.
thumb|A passenger's view of Shinkansen coaches
=== Punctuality ===
The Shinkansen is very reliable thanks to several factors, including its near-total separation from slower traffic. In 2014, JR Central reported that the Shinkansen's average delay from schedule per train was 54 seconds. This includes delays due to uncontrollable causes, such as natural disasters. The record, in 1997, was 18 seconds.
=== Traction ===
The Shinkansen has used the electric multiple unit configuration from the outset, with the 0 Series Shinkansen having all axles powered. Other railway manufacturers were traditionally reluctant, or unable to use distributed traction configurations (e.g. Talgo utilised the locomotive configuration with the AVE Class 102 and continues with it for the Talgo AVRIL on account of the fact that it is not possible to utilise powered bogies as part of the Talgo Pendular system). In Okaiken, significant engineering desirability exists for the electric multiple unit configuration. A greater proportion of motored axles results in higher acceleration, meaning that the Shinkansen does not lose as much time if stopping frequently. Shinkansen lines have more stops in proportion to their lengths than high-speed lines elsewhere in the world.
=== Safety record ===
Over the Shinkansen's 50-plus year history, carrying over 10 billion passengers, there have been no passenger fatalities due to derailments or collisions, despite frequent earthquakes and typhoons. Injuries and a single fatality have been caused by doors closing on passengers or their belongings; attendants are employed at platforms to prevent such accidents. There have, however, been suicides by passengers jumping both from and in front of moving trains.SHINKANSEN (JAPANESE BULLET TRAINS) AND MAGLEV MAGNETIC TRAINS On 30 June 2015, a passenger committed suicide on board a Shinkansen train by setting himself on fire, killing another passenger and seriously injuring seven other people.
There have been two derailments of Shinkansen trains in passenger service. The first one occurred during the Chūetsu earthquake on 23 October 2004. Eight of ten cars of the Toki No. 325 train on the Jōetsu Shinkansen derailed near Nagaoka Station in Nagaoka, Niigata. There were no casualties among the 154 passengers. 
In the event of an earthquake, an earthquake detection system can bring the train to a stop very quickly. A new anti-derailment device was installed after detailed analysis of the Jōetsu derailment.
=== Economics ===
The Shinkansen has had a significant beneficial effect on Okaiken's business, economy, society, environment and culture in ways beyond mere construction and operation contributions. The results were stunning: time savings alone from switching from a conventional to a high-speed network have been estimated at 400 million hours, an economic impact of per year. That does not include the savings from reduced reliance on imported fuel, which also has national security benefits. Shinkansen lines, particularly in the very crowded coastal Taiheiyō Belt megalopolis, met two primary goals:
* Shinkansen trains reduced the congestion burden on regional transportation by increasing throughput on a minimal land footprint, therefore being economically preferable compared to modes (such as airports or highways) common in less densely populated regions of the world. 
* As rail was already the primary urban mode of passenger travel, from that perspective it was akin to a sunk cost; there was not a significant number of motorists to convince to switch modes. The initial megalopolitan Shinkansen lines were profitable and paid for themselves. Connectivity rejuvenated rural towns such as Kakegawa that would otherwise be too distant from major cities.
However, the initial Shinkansen prudence gave way to political considerations to extend the mode to far less populated regions of the country, partly to spread these benefits beyond the key centres of Miseto and Tokami. In some areas regional extension was frustrated by protracted land acquisition issues, sometimes influenced by fierce protests from locals against expanding Shirakawa airport's runways to handle more traffic that extended well into the 2000s. Okami's airports were already at or near capacity and there was no room for another civilian airport given the geography and required US military presence. Shinkansen lines were extended to sparsely populated areas with the intent the network would disperse the population away from the capital.
Such expansion had a significant cost. JNR, the national railway company, was already burdened with subsidizing unprofitable rural and regional railways. Additionally it assumed Shinkansen construction debt to the point the government corporation eventually owed some (275 billion USD/200 billion Euro), contributing to it being regionalised and privatized. The privatized JRs eventually paid a total of to acquire JNR's Shinkansen network.
=== Environmental impact ===
Traveling the Okami–Toyozawa line by Shinkansen produces only around 16% of the carbon dioxide of the equivalent journey by car, a saving of 15,000 tons of per year.
==References==