Editing Maglev (section)

{{Short description|Train system using magnetic levitation}}
{{About|transportation|the phenomenon|Magnetic levitation|other uses}}
{{Use dmy dates|date=December 2014}}
{{POV|talk=POV|date=May 2023}}
[[File:Transrapid 09.jpg|thumb|[[Transrapid]] 09 at the [[Emsland test facility]] in Lower Saxony, Germany]]
[[File:Transrapid Shanghai maglev train ride.webm|thumbtime=22|thumb|right|A full trip on the [[Shanghai Transrapid]] maglev train]]
[[File:Linimo-2.jpg|thumb|right|Example of low-speed urban maglev system, [[Linimo]]]]
'''Maglev''' (derived from ''[[magnetic levitation]]'') is a system of [[rail transport]] whose [[rolling stock]] is levitated by [[electromagnet]]s rather than rolled on wheels, eliminating [[rolling resistance]].<ref>{{cite web |date=27 February 2017 |title=Japanese Maglev Train: World's Fastest Bullet Train – JRailPass |url=https://www.jrailpass.com/blog/maglev-bullet-train |url-status=live |archive-url=https://web.archive.org/web/20220715234852/https://www.jrailpass.com/blog/maglev-bullet-train |archive-date=15 July 2022 |access-date=18 July 2022}}</ref><ref>{{cite book |doi=10.1016/B978-0-12-802314-3.00009-3 |quote=Maglev train systems use powerful electromagnets to float the trains over a guideway, instead of the old steel wheel and track system. A system called electromagnetic suspension suspends, guides, and propels the trains. A large number of magnets provide controlled tension for lift and propulsion along a track. |chapter=Emerging Green Industrial Revolution Technologies |title=The Green Industrial Revolution |date=2015 |last1=Clark |first1=Woodrow W. |last2=Cooke |first2=Grant |pages=173–190 |isbn=978-0-12-802314-3 }}</ref><ref>{{cite journal |last1=Qadir |first1=Zakria |last2=Munir |first2=Arslan |last3=Ashfaq |first3=Tehreem |last4=Munawar |first4=Hafiz Suliman |last5=Khan |first5=Muazzam A. |last6=Le |first6=Khoa |title=A prototype of an energy-efficient MAGLEV train: A step towards cleaner train transport |journal=Cleaner Engineering and Technology |date=2021 |volume=4 |pages=100217 |doi=10.1016/j.clet.2021.100217 |doi-access=free|bibcode=2021CEngT...400217Q }}</ref>

Compared to conventional railways, maglev trains have higher top speeds, superior acceleration and deceleration, lower maintenance costs, improved [[Grade (slope)|gradient]] handling, and lower noise. However, they are more expensive to build, cannot use existing infrastructure, and use more energy at high speeds.<ref>{{Cite web |date=17 January 2018 |title=Will maglev ever become mainstream? |url=https://www.railway-technology.com/features/will-maglev-ever-become-mainstream/ |url-status=live |archive-url=https://web.archive.org/web/20210604033721/https://www.railway-technology.com/features/will-maglev-ever-become-mainstream/ |archive-date=4 June 2021 |access-date=2021-06-04 |website=www.railway-technology.com |language=en-GB}}</ref>

Maglev trains have set [[railway speed record|several speed records]]. The train speed record of {{convert|603|km/h|0|abbr=on}} was set by the experimental Japanese [[L0 Series]] maglev in 2015.<ref name="guardian201504212">{{cite web |date=21 April 2015 |title=Japan's maglev train breaks world speed record with 600km/h test run |url=https://www.theguardian.com/world/2015/apr/21/japans-maglev-train-notches-up-new-world-speed-record-in-test-run |url-status=live |archive-url=https://web.archive.org/web/20191206145023/https://www.theguardian.com/world/2015/apr/21/japans-maglev-train-notches-up-new-world-speed-record-in-test-run |archive-date=6 December 2019 |access-date=21 April 2015 |work=The Guardian |publisher=Guardian News and Media Limited |location=United Kingdom}}</ref> From 2002 until 2021, the record for the highest operational speed of a passenger train of {{convert|431|km/h}} was held by the [[Shanghai maglev train]], which uses German [[Transrapid]] technology.<ref name=":1">{{Cite web |title=Everything about Shanghai Maglev Train: Speed, Station, Map, Ticket & Price, Facts... |url=https://www.chinadiscovery.com/shanghai/shanghai-maglev.html |access-date=2023-11-19 |website=www.chinadiscovery.com |language=en}}</ref> The service connects [[Shanghai Pudong International Airport]] and the outskirts of central [[Pudong]], [[Shanghai]]. At its historical top speed, it covered the distance of {{convert|30.5|km|0}} in just over 8{{nbsp}}minutes.

Different maglev systems achieve levitation in different ways, which broadly fall into two categories: [[Electromagnetic suspension|electromagnetic suspension (EMS)]] and [[Electrodynamic suspension|electrodynamic suspension (EDS)]]. Propulsion is typically provided by a [[linear motor]].<ref>{{Cite journal |last=Yaghoubi |first=Hamid |date=2013-03-27 |title=The Most Important Maglev Applications |journal=Journal of Engineering |language=en |volume=2013 |pages=e537986 |doi=10.1155/2013/537986 |doi-access=free }}</ref> The power needed for levitation is typically not a large percentage of the overall energy consumption of a high-speed maglev system.<ref>[http://www.transrapid.de/cgi-tdb/en/basics.prg?a_no=41 Transrapid] {{webarchive|url=https://web.archive.org/web/20130927190155/http://www.transrapid.de/cgi-tdb/en/basics.prg?a_no=41 |date=27 September 2013 }} uses more power for air conditioning</ref> Instead, overcoming [[Drag (physics)|drag]] takes the most energy. [[Vactrain]] technology has been proposed as a means to overcome this limitation.

Despite over a century of research and development, there are only seven operational maglev trains today — four in China, two in South Korea, and one in Japan.<ref>{{Cite web|title=The Six Operational Maglev Lines in 2018|url=https://www.maglev.net/six-operational-maglev-lines-in-2018|access-date=2021-11-23|website=www.maglev.net|archive-date=28 November 2020|archive-url=https://web.archive.org/web/20201128221743/https://www.maglev.net/six-operational-maglev-lines-in-2018|url-status=live}}</ref><ref name=":0">{{Cite web |date=2022-10-05 |title=High-speed rail trains are stalled in the US—and that might not change for a while |url=https://www.popsci.com/technology/high-speed-trains-hyperloop-history/ |url-status=live |archive-url=https://web.archive.org/web/20221226023720/https://www.popsci.com/technology/high-speed-trains-hyperloop-history/ |archive-date=26 December 2022 |access-date=2022-12-26 |website=Popular Science |language=en-US}}</ref>

The first intercity maglev line is being built in China and will connect [[Changsha]] and [[Liuyang]] cities in Hunan Province.<ref>{{cite web | url=https://www.globalconstructionreview.com/china-begins-work-on-1-5bn-maglev-track/ | title=China begins work on $1.5bn maglev track | date=9 December 2024 }}</ref><ref>{{cite web | url=https://www.railjournal.com/passenger/main-line/china-begins-construction-of-inter-city-maglev/ | title=China begins construction of inter-city maglev | date=15 November 2024 }}</ref>