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[[File:Hyperloop all cutaway.png|thumb|Concept art of hyperloop inner workings|265x265px]]
 
'''Hyperloop''' is a proposed high-speed [[transport]]ation system for both passengers and freight.<ref>{{cite web |last=Simon |first=Joanna |url=https://wagner.nyu.edu/rudincenter/2017/02/primer-hyperloop-travel-how-far-future |title=A Primer on Hyperloop Travel: How far off is the Future? |publisher=[[Rudin Center for Transportation Policy & Management]], [[New York University]] |access-date=2024-05-24}}</ref> The concept was published by entrepreneur [[Elon Musk]] in a 2013 [[white paper]], where the hyperloop was described as a transportation system using capsules supported by an [[air bearing|air-bearing surface]] within a low-pressure tube.<ref name="Alpha SpaceX" /><ref>{{cite journal |last1=Premsagar |first1=Smriti |last2=Kenworthy |first2=Jeffrey |date=2022 |title=A Critical Review of Hyperloop (Ultra-High Speed Rail) Technology: Urban and Transport Planning, Technical, Environmental, Economic, and Human Considerations |journal=[[Frontiers in Sustainable Cities]] |volume=4 |doi=10.3389/frsc.2022.842245 |doi-access=free|bibcode=2022FrSC....4.2245P }}</ref> Hyperloop systems have three essential elements: tubes, pods, and terminals. The tube is a large, sealed [[Vacuum#Vacuum-driven machines|low-pressure system]] (typically a long tunnel). The pod is a coach at [[atmospheric pressure]] that experiences low [[Drag (physics)|air resistance]] or friction inside the tube<ref name="mechsite2019092">{{cite web |last1=Opgenoord |first1=Max M. J. |title=How does the aerodynamic design implement in hyperloop concept? |url=https://mechanicalsite.com/446/how-does-the-aerodynamic-design-implement-hyperloop-concept |url-status=usurped |archive-url=https://web.archive.org/web/20191003205826/https://mechanicalsite.com/446/how-does-the-aerodynamic-design-implement-hyperloop-concept |archive-date=3 October 2019 |access-date=16 September 2019 |website=Mechanical Engineering |publisher=MIT - Massachusetts Institute of Technology}}</ref><ref>{{cite journal |last1=Lang |first1=Alex J. |last2=Connolly |first2=David P. |last3=de Boer |first3=Gregory |last4=Shahpar |first4=Shahrokh |last5=Hinchliffe |first5=Benjamin |last6=Gilkeson |first6=Carl A. |date=2024 |title=A review of Hyperloop aerodynamics |journal=Computers & Fluids |volume=273 |pages=106202 |doi=10.1016/j.compfluid.2024.106202}}</ref> using [[Maglev|magnetic propulsion]] (in the initial design, augmented by a [[ducted fan]]). The terminal handles pod arrivals and departures. The hyperloop, in the form proposed by Musk, differs from other [[Vactrain|vactrains]] by relying on residual air pressure inside the tube to provide lift from [[Aerofoil|aerofoils]] and propulsion by fans; however, many subsequent variants using the name "hyperloop" have remained relatively close to the core principles of vactrains.<ref>{{Cite web |last=Garfield |first=Leanna |title=15 remarkable images that show the 200-year evolution of the Hyperloop |url=https://www.businessinsider.com/history-hyperloop-pneumatic-tubes-as-transportation-2017-8#in-1799-inventor-george-medhurst-proposed-an-idea-to-move-goods-through-cast-iron-pipes-using-air-pressure-in-1844-he-built-a-railway-station-for-passenger-carriages-in-london-that-relied-on-pneumatics-until-1847-1 |access-date=2024-12-08 |website=Business Insider |language=en-US}}</ref><ref>{{Cite web |date=March 25, 2021 |title=Timeline: tracing the evolution of hyperloop rail technology - Rainway-Technology |url=https://rail.nridigital.com/future_rail_mar21/hyperloop_rail_system_timeline}}</ref>
 
Hyperloop was teased by Elon Musk at a 2012 speaking event, and described as a "fifth mode of transport".<ref name="PandoDaily Hyperloop">{{cite web |title=Pando Monthly presents a fireside chat with Elon Musk |url=https://pando.com/2012/07/12/pandomonthly-presents-a-fireside-chat-with-elon-musk/ |website=pando.com |publisher=PandoDaily |access-date=15 July 2017 |date=13 July 2012 |archive-date=16 July 2017 |archive-url=https://web.archive.org/web/20170716135721/https://pando.com/2012/07/12/pandomonthly-presents-a-fireside-chat-with-elon-musk/ |url-status=live}}</ref> Musk released details of an alpha-version in a [[white paper]] on 22 August 2013, in which the hyperloop design incorporated reduced-pressure tubes with [[pressurized]] capsules riding on [[air bearing]]s driven by [[linear induction motor]]s and [[axial compressor]]s.<ref name="gm20130822" /> The white paper showed an example hyperloop route running from the [[Los Angeles]] region to the [[San Francisco Bay Area]], roughly following the [[Interstate 5 in California|Interstate 5]] corridor.<ref name="Alpha SpaceX" /> Some transportation analysts challenged the cost estimates in the white paper, with some predicting that a hyperloop would run several billion dollars higher.<ref name="NYT-Bilton" /><ref name="AJE" /><ref name="HuffPoAstronomical" />
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A [[Technical University of Munich]] hyperloop set a speed record of {{cvt|463|km/h|mph|0}} in July 2019<ref name=brde20210521/><ref name=verge20190722/> at the [[Hyperloop pod competition|pod design competition]] hosted by SpaceX in [[Hawthorne, California|Hawthorne]], California.<ref>{{cite news |last1=Etherington |first1=Darrell |title=Here's a first look at the SpaceX Hyperloop test track |url=https://techcrunch.com/2016/09/02/heres-a-first-look-at-the-spacex-hyperloop-test-track/ |publisher=TechCrunch |date=2 September 2016 |access-date=25 November 2016 |archive-date=15 September 2016 |archive-url=https://web.archive.org/web/20160915205721/https://techcrunch.com/2016/09/02/heres-a-first-look-at-the-spacex-hyperloop-test-track/ |url-status=live}}</ref> [[Virgin Hyperloop]] conducted the first human trial in November 2020 at its test site in [[Las Vegas]], reaching a top speed of {{cvt|107|mph|km/h|0|order=flip}}.<ref>{{cite web |url=https://www.theguardian.com/technology/2020/nov/09/first-passengers-travel-in-virgins-levitating-hyperloop-pod-system |title=First passengers travel in Virgin's levitating hyperloop pod system |work=The Guardian |date=9 November 2020 |access-date=10 November 2020 |archive-date=10 November 2020 |archive-url=https://web.archive.org/web/20201110032806/https://www.theguardian.com/technology/2020/nov/09/first-passengers-travel-in-virgins-levitating-hyperloop-pod-system |url-status=live}}</ref> Swisspod Technologies unveiled a 1:12 scale testing facility in a circular shape to simulate an "infinite" hyperloop trajectory in July 2021 on the EPFL campus at [[Lausanne]], [[Switzerland]].<ref name="epfl.ch"/> In 2023, a new European effort to standardize "hyperloop systems" released a draft standard.<ref name=cencenelec202301/>
 
[[Hyperloop One]], one of the best well-known and well-funded players in the hyperloop space, declared bankruptcy and ceased operations on 31 December 2023. Other companies continue to pursue hyperloop technology development.<ref name=hyperloopOneShutdown20231221/>
 
==History==
Musk first mentioned that he was thinking about a concept for a "fifth mode of transport", calling it the ''Hyperloop'', in July 2012 at a [[Pando Daily]] event in [[Santa Monica, California]]. This hypothetical high-speed mode of transportation would have the following characteristics: immunity to weather, collision free, twice the speed of a plane, low power consumption, and energy storage for 24-hour operations.<ref name="pando_video"/> The name ''Hyperloop'' was chosen because it would go in a loop. In May 2013, Musk likened Hyperloop to a "cross between a [[Concorde]] and a [[railgun]] and an [[air hockey]] table".<ref name="atd20130530"/> By 2016, Musk envisioned that more advanced versions could potentially be able to go at [[hypersonic speed]].<ref name="youtube20160131">{{cite AV media |url=https://www.youtube.com/watch?v=ab2VVp1GfmA |title=Elon Musk speaks at the Hyperloop Pod Award Ceremony |publisher=YouTube |date=30 January 2016 |access-date=2 February 2016 |archive-date=26 October 2017 |archive-url=https://web.archive.org/web/20171026083851/https://www.youtube.com/watch?v=ab2VVp1GfmA |url-status=live}}</ref>
 
From late 2012 until August 2013, a group of engineers from both [[Tesla Motors|Tesla]] and SpaceX worked on the modeling of Musk's Hyperloop concept.<ref name="gm20130813"/> An early system conceptual model was published on both the Tesla and SpaceX websites<ref name="Alpha SpaceX"/><ref name="Alpha Tesla" /> which describes one potential design, function, pathway, and cost of a hyperloop system.<ref name="Alpha SpaceX" /> In the alpha design, pods were envisioned to accelerate to cruising speeds gradually using [[Linear motor|linear electric motors]] and glide above their track on [[air bearing]]s through tubes above ground on columns or below ground in tunnels to avoid the challenges of [[grade crossing]]s. An ideal hyperloop system was estimated to be more energy-efficient,<ref name="EDS power consumption">{{cite journal |url=https://www.pes-publications.ee.ethz.ch/uploads/tx_ethpublications/22_Scaling_laws_for_electrodynamic_suspension_Flankl_accepted-version.pdf |title=Scaling laws for electrodynamic suspension in high-speed transportation |last1=Flankl |first1=Michael |last2=Weller dieck |first2=Tobias |last3=Tüysüz |first3=Arda |last4=Kolar |first4=Johann W. |journal=IET Electric Power Applications |volume=12 |issue=3 |pages=357–364 |date=November 2017 |access-date=2 February 2018 |doi=10.1049/iet-epa.2017.0480 |archive-date=26 January 2018 |archive-url=https://web.archive.org/web/20180126012539/https://www.pes-publications.ee.ethz.ch/uploads/tx_ethpublications/22_Scaling_laws_for_electrodynamic_suspension_Flankl_accepted-version.pdf |url-status=dead}}</ref><ref name="ESC Hyperloop">{{cite AV media |url=http://www.esc.ethz.ch/news/archive/2017/11/energy-efficiency-of-an-electrodynamically-levitated-hyperloop-pod.html |title=Energy Efficiency of an Electrodynamically Levitated Hyperloop Pod |publisher=Energy Science Center |date=29 November 2017 |access-date=2 February 2018 |archive-date=20 November 2022 |archive-url=https://web.archive.org/web/20221120065425/https://esc.ethz.ch/news/archive/2017/11/energy-efficiency-of-an-electrodynamically-levitated-hyperloop-pod.html |url-status=live}}</ref> quiet, and [[vehicular automation|autonomous]] than existing modes of mass transit in the 2010s.<ref>{{cite journal |last1=Kassebi |first1=Oussema |last2=Siegfried |first2=Patrick |title=The Hyperloop: The innovative logistic technology |journal=Journal of Road and Traffic Engineering |date=2022 |volume=68 |issue=1 |pages=11–16 |doi=10.31075/PIS.68.01.02 |doi-access=free}}</ref> The Hyperloop Alpha was released as an [[Open-source model|open source]] design. Musk invited feedback to "see if the people can find ways to improve it".<ref name="globemail20130812"/> The trademark "''HYPERLOOP''", applicable to "high-speed transportation of goods in tubes" was issued to SpaceX on 4 April 2017.<ref>{{cite web| title=Word Mark HYPERLOOP|url=http://tmsearch.uspto.gov/bin/showfield?f=doc& state=4810:6uwa73.2.7|publisher=U.S. Patent and Trademark Office| access-date=10 September 2017|archive-date=21 July 2022|archive-url=https://web.archive.org/web/20220721205854/https://tmsearch.uspto.gov/bin/showfield?f=doc&state=4810:6uwa73.2.7|url-status=livedead}}</ref>{{Failed verification|date=May 2025|reason=USPTO search does not show SpaceX ever owning the trademark.}}<ref>{{cite news|last1=Muoio|first1=Danielle| title=Everything we know about Elon Musk's ambitious Hyperloop plan|url=httphttps://www.businessinsider.com/elon-musk-hyperloop-plan-boring-company-2017-8|access-date=1026 SeptemberMay 20172025|publisher=Business Insider |date=17 August 2017|archive-date=19 October 2022|archive-url=https://web.archive.org/web/20221019025704/https://www.businessinsider.com/elon-musk-hyperloop-plan-boring-company-2017-8|url-status=live}}</ref>
 
On 15 June 2015, SpaceX announced that it would build a {{convert|1|mi|km|-long| adj=mid}} [[Hyperloop pod competition#Test track|Hyperloop test track]] located next to SpaceX's [[Hawthorne, California|Hawthorne]] facility.<ref name="CNNmoney-15-6-15"/><ref name="SFchronicle-6-15-15" /> The track was completed and used to test pod designs supplied by third parties in the competition.
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As of 21 December 2023, [[Hyperloop One]], the former, rebranded Virgin Hyperloop, has terminated operations.<ref name=hyperloopOneShutdown20231221>{{cite news|last=McBride |first=Sarah |title=Hyperloop One to Shut Down After Failing to Reinvent Transit |url=https://www.bloomberg.com/news/articles/2023-12-21/hyperloop-one-to-shut-down-after-raising-millions-to-reinvent-transit|publisher=Bloomberg |date=21 December 2023}}</ref>
 
Work in China on a similar project continued. In July 2024, [[CASIC]] conducted a test of their low-vacuum rail system.<ref>{{Cite news |last=CNSAWatcher |date=August 4, 2024 |title=CASIC achieves milestone |url=https://x.com/CNSAWatcher/status/1820372753783873806}}</ref>
 
==Theory and operation==
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The much-older [[vactrain]] concept resembles a [[high-speed rail]] system without substantial [[Drag (physics)|air resistance]] by employing [[maglev|magnetically levitating]] trains in [[vacuum|evacuated]] (airless) or partly evacuated tubes. However, the difficulty of maintaining a vacuum over large distances has prevented this type of system from ever being built. By contrast, the Hyperloop alpha concept was to operate at approximately {{convert|1|mbar|Pa|spell=in|lk=on}} of pressure and requires the air for levitation.<ref name="nova20130813"/>
 
=== Initial design concept ===
== Technical Challenges ==
Implementing a full-scale, operational hyperloop system faces numerous engineering and scientific hurdles that go beyond the basic concept. These challenges must be addressed for the system to be considered feasible, safe, and economically viable.<ref name="PremsagarKenworthyCritReview"/>
 
The hyperloop alpha concept envisioned operation by sending specially designed "capsules" or "pods" through a steel tube maintained at a partial vacuum. In Musk's original concept, each capsule would float on a {{convert|0.5-1.3|mm|in|2|order=flip|abbr=on}} layer of air provided under pressure to [[air caster|air-caster]] "skis", similar to how pucks are levitated above an air hockey table, while still allowing higher speeds than wheels can sustain. With [[rolling resistance]] eliminated and air resistance greatly reduced, the capsules can [[gliding flight|glide]] for the bulk of the journey. In the alpha design concept, an electrically driven [[ducted fan|inlet fan]] and [[axial compressor]] would be placed at the nose of the capsule to "actively transfer high-pressure air from the front to the rear of the vessel", resolving the problem of air pressure building in front of the vehicle, slowing it down (the [[Kantrowitz limit]]). A fraction of the air was to be shunted to the skis for additional pressure, augmenting that gain passively from lift due to their shape.<ref name="Alpha SpaceX" />
=== Tube Integrity and Vacuum Maintenance ===
Creating and maintaining a near-vacuum environment over hundreds of kilometers presents significant challenges.
*'''Sealing:''' The tube must be effectively sealed against air leaks along its entire length, including at joints, stations, and airlocks. Even small leaks could compromise the low-pressure environment, increasing drag and requiring continuous pumping.<ref name="PremsagarKenworthyCritReview" />
*'''Structural Integrity:''' The tube must withstand the substantial pressure difference between the low-pressure interior and the atmospheric exterior (approximately 1 atm or 101.3 kPa, equating to roughly 10 tonnes of force per square meter at near vacuum<ref>{{cite web |title=Pressure Force Calculation |url=https://www.omnicalculator.com/physics/pressure-force |access-date=2025-04-08 |website=Omni Calculator}} Note: Calculation based on atmospheric pressure ≈ 101.3 kPa.</ref>). The alpha design specified steel tubes with a wall thickness of around 20-25 mm (0.8-1.0 in).<ref name="Alpha SpaceX" /><sup>(Section 4.1, 4.2)</sup> A simple calculation for the compressive hoop stress in a 2.5 m diameter, 25 mm thick steel tube under this pressure yields approximately 5.1 MPa, which is significantly below the yield strength of typical steel (often 250 MPa or higher). However, the primary failure mode for such structures under external pressure is not yielding but [[Buckling|buckling instability]]. While theoretical calculations suggest a perfect cylinder of these dimensions could resist buckling from atmospheric pressure, real-world imperfections significantly reduce buckling strength. Therefore, robust engineering design, likely incorporating stiffening rings (as mentioned in the alpha design<ref name="Alpha SpaceX" /><sup>(Section 4.2)</sup>) to increase stability, is essential rather than relying solely on basic material strength. The design must also account for ground settlement, seismic activity, and potential impacts.<ref name="PremsagarKenworthyCritReview" />
*'''Pumping Systems:''' A large network of powerful and reliable vacuum pumps would be needed initially to evacuate the tube and continuously thereafter to remove any ingressing air from leaks and [[Outgassing|material outgassing]].<ref name="Alpha SpaceX" /><sup>(Section 4.3)</sup> The energy required is substantial.<ref name="PremsagarKenworthyCritReview" /> Calculating the precise energy is complex, but estimates can illustrate the scale. For the initial evacuation of a hypothetical 600 km route with a 2.5 m diameter tube down to 100 Pascals (Musk's target), the theoretical minimum energy required (assuming isothermal removal) is on the order of 600,000 kWh.<ref>Calculation: Volume ≈ π*(1.25m)²*600,000m ≈ 2.95 million m³. Work ≈ V*P_atm*ln(P_atm/P_final) ≈ (2.95e6 m³) * (101300 Pa) * ln(101300/100) ≈ 2.07e12 J. Energy ≈ 2.07e12 J / (3.6e6 J/kWh) ≈ 575,000 kWh.</ref> However, real-world pump system efficiencies are far lower than theoretical ideals (potentially 10-50% overall efficiency for such a system), meaning the actual energy consumed for initial pump-down could be significantly higher, likely several million kWh. Critically, energy is also required ''continuously'' to counteract gas influx from leaks through seals and welds along the tube length, and from outgassing of the tube's inner walls. This steady-state pumping load depends heavily on the chosen materials, construction quality, and seal technology, but represents a continuous operational energy cost.<ref name="PremsagarKenworthyCritReview" /> The alpha design suggested pumps roughly every 5 miles (8 km), indicating the anticipated need for distributed, ongoing power consumption for vacuum maintenance.<ref name="Alpha SpaceX" /><sup>(Section 4.3)</sup>
 
In the alpha-level concept, passenger-only pods were to be {{convert|2.23|m|order=flip|abbr=on}} in diameter and were projected to reach a top speed of {{convert|760|mph|km/h|abbr=on}} (Machto ~1.0maintain inaerodynamic theefficiency.<ref low-pressurename="Alpha tube)SpaceX" to/><sup> maintain(Section aerodynamic efficiency4.4)</sup> The design proposed passengers experience a maximum inertial [[g-force|acceleration]] of 0.5 g, about 2 or 3 times that of a commercial airliner on takeoff and landing.<ref{{citation nameneeded|date="AlphaSeptember SpaceX" /><sup> (Section 4.4)</sup>2021}}
=== Aerodynamics and the Kantrowitz Limit ===
Even in a partial vacuum, air resistance becomes significant at the proposed high speeds.<ref name="LangConnollyReview2024"/>
*'''[[Kantrowitz limit]]:''' As a pod travels through the confined tube, air builds up in front of it. If the gap between the pod and the tube wall is too small relative to the pod's speed (high blockage ratio), the air cannot flow around the pod efficiently, causing the air to compress and potentially choke the flow near Mach 1. This dramatically increases drag and necessitates managing the air ahead of the pod.<ref name="Alpha SpaceX" /><sup>(Section 4.4)</sup><ref name="OpgenoordCaplanAIAA2017"/><ref name="LangConnollyReview2024" /> Musk's alpha design proposed an onboard compressor to actively transfer air from the front to the rear, though this adds complexity, weight, and energy consumption to the pod.<ref name="Alpha SpaceX" /><sup>(Section 4.4)</sup> Alternative solutions involve larger tube diameters (reducing blockage ratio) or operating at lower speeds.<ref name="openmdao"/><ref name="Chin2015"/>
*'''Air Management:''' The interaction of the high-speed pod with the residual air, especially if using air bearings or aerodynamic lift surfaces as initially proposed, is complex and requires precise control.<ref name="mechsite2019092" /><ref name="LangConnollyReview2024" />
 
=== Levitation and Propulsion ===
Efficiently levitating and propelling pods requires advanced, reliable systems.
*'''[[Maglev]] Systems:''' Most current hyperloop concepts rely on magnetic levitation (maglev) rather than the air bearings proposed in the alpha design, due to challenges with air bearing stability and efficiency at speed.<ref name="PremsagarKenworthyCritReview" /> Implementing stable maglev over long distances, particularly on elevated pylons subject to movement or vibration, is challenging and expensive.<ref name="PremsagarKenworthyCritReview" /> Power requirements for levitation and propulsion, especially during acceleration, are significant.<ref name="EDS power consumption"/><ref name="ESC Hyperloop"/>
*'''Linear Motors:''' Linear electric motors embedded in the track or tube are typically proposed for propulsion.<ref name="Alpha SpaceX" /><sup>(Section 4.5)</sup> These require precise alignment with the pod and substantial power infrastructure along the entire route.<ref name="PremsagarKenworthyCritReview" />
 
=== Thermal Expansion ===
Long steel tubes exposed to varying ambient temperatures will expand and contract significantly. A several hundred kilometer steel tube could change length by hundreds of meters between temperature extremes.<ref>{{cite web|title=Thermal Expansion - Linear Expansion Coefficients|url=https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html|website=Engineering Toolbox|access-date=8 April 2025}} Note: Calculation based on ~12 µm/(m·°C) for steel and a large temperature range.</ref> The alpha design proposed slip joints consisting of telescoping tubes with multiple seals to accommodate this, allowing axial movement while maintaining the vacuum seal.<ref name="Alpha SpaceX" /><sup>(Section 4.2)</sup> Designing reliable, long-lasting expansion joints capable of maintaining a vacuum seal under these conditions is a critical challenge.<ref name="PremsagarKenworthyCritReview" />
 
=== Alignment and Stability ===
Maintaining the precise alignment required for high-speed travel in a tube (tolerances likely in millimeters), especially over long distances and potentially across seismic zones, is a major challenge.<ref name="PremsagarKenworthyCritReview" /> Even minor misalignments or track irregularities could cause significant instability, vibration, or unsafe conditions at speeds approaching [[Mach 1]].<ref name="verge20130816"/> Elevated sections on pylons are particularly susceptible to ground movement, wind forces, and thermal effects impacting alignment.<ref name="PremsagarKenworthyCritReview" /><ref name="Alpha SpaceX" /><sup>(Section 4.1)</sup>
 
=== Safety and Emergency Systems ===
Ensuring passenger safety within a sealed, low-pressure environment presents unique challenges.<ref name="PremsagarKenworthyCritReview" />
*'''Decompression:''' A breach in the tube wall could lead to rapid, potentially catastrophic, decompression and expose pods to extreme aerodynamic forces. Systems for rapidly detecting breaches and safely stopping or diverting pods are crucial.<ref name="PremsagarKenworthyCritReview" /><ref name="Mercury-2016-09-16"/> The alpha design included emergency brakes on the pods and suggested pressure sensors along the tube.<ref name="Alpha SpaceX" /><sup>(Section 4.6)</sup>
*'''Emergency Evacuation:''' Evacuating passengers from a pod stopped within the tube (e.g., due to power failure or malfunction) potentially miles from a station is complex. Pods would need emergency oxygen supplies. Procedures might involve rescue vehicles within the tube, repressurization of sections, or potentially parallel emergency access tunnels, which would significantly increase cost.<ref name="PremsagarKenworthyCritReview" />
*'''Emergency Braking:''' Safely decelerating a pod from very high speeds requires robust braking systems that can function reliably within the low-pressure environment, potentially independent of the main propulsion and levitation systems.<ref name="Alpha SpaceX" /><sup>(Section 4.6)</sup>
 
=== Switching ===
Efficiently switching pods between different lines or diverting them to stations without significantly slowing down the main line traffic, and doing so within the vacuum environment, requires innovative and reliable mechanisms. Solutions involving mechanical switches within low-pressure sections or non-mechanical switching using magnetic fields have been proposed and demonstrated on a small scale by companies like Hardt Hyperloop.<ref name="eit.europa.eu"/>
 
=== Initial design concept ===
 
The hyperloop alpha concept envisioned operation by sending specially designed "capsules" or "pods" through a steel tube maintained at a partial vacuum. In Musk's original concept, each capsule would float on a {{convert|0.5-1.3|mm|in|2|order=flip|abbr=on}} layer of air provided under pressure to [[air caster|air-caster]] "skis", similar to how pucks are levitated above an air hockey table, while still allowing higher speeds than wheels can sustain. With [[rolling resistance]] eliminated and air resistance greatly reduced, the capsules can [[gliding flight|glide]] for the bulk of the journey. In the alpha design concept, an electrically driven [[ducted fan|inlet fan]] and [[axial compressor]] would be placed at the nose of the capsule to "actively transfer high-pressure air from the front to the rear of the vessel", resolving the problem of air pressure building in front of the vehicle, slowing it down (the [[Kantrowitz limit]]). A fraction of the air was to be shunted to the skis for additional pressure, augmenting that gain passively from lift due to their shape.<ref name="Alpha SpaceX" />
 
In the alpha-level concept, passenger-only pods were to be {{convert|2.23|m|order=flip|abbr=on}} in diameter and were projected to reach a top speed of {{convert|760|mph|km/h|abbr=on}} (Mach ~1.0 in the low-pressure tube) to maintain aerodynamic efficiency. The design proposed passengers experience a maximum inertial [[g-force|acceleration]] of 0.5 g, about 2 or 3 times that of a commercial airliner on takeoff and landing.<ref name="Alpha SpaceX" /><sup> (Section 4.4)</sup>
 
===Proposed routes===
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Several routes have been proposed that meet the distance conditions for which a hyperloop is hypothesized to provide improved transport times: under approximately {{Convert|1500|km|miles|abbr=off}}.<ref name=zdnet20200418>{{Cite web|last=Ranger|first=Steve|title=What is Hyperloop? Everything you need to know about the race for super-fast travel|url=https://www.zdnet.com/article/what-is-hyperloop-everything-you-need-to-know-about-the-future-of-transport/|access-date=18 April 2020|website=ZDNet|language=en|archive-date=30 October 2020|archive-url=https://web.archive.org/web/20201030113256/https://www.zdnet.com/article/what-is-hyperloop-everything-you-need-to-know-about-the-future-of-transport/|url-status=live}}</ref> Route proposals range from speculation described in company releases<!-- and this speculative material is often [[WP:UNDUE]] -->, to [[business case]]s, to signed agreements.
 
==== ChinaSouth Korea ====
 
An agreement was signed in June 2017 to co-develop a hyperloop line between [[Seoul]] and [[Busan]], South Korea.<ref name=imeche20170719>{{cite news |url=http://www.imeche.org/news/news-article/investment-in-hyperloop-routes-speeds-up |title=Investment in hyperloop routes speeds up |first=Jørn |last=Madslien |publisher=Institute of Mechanical Engineers |___location=UK |date=19 July 2017 |access-date=11 August 2017 |archive-date=25 May 2021 |archive-url=https://web.archive.org/web/20210525055436/https://www.imeche.org/news/news-article/investment-in-hyperloop-routes-speeds-up |url-status=live}}</ref><ref name=wired20170620>{{cite magazine |url=https://www.wired.com/story/hyperloop-south-korea/ |title=South Korea Is Building a Hyperloop |first=Alex |last=Davies |magazine=Wired |___location=US |date=20 June 2017 |access-date=16 March 2019 |archive-date=18 October 2021 |archive-url=https://web.archive.org/web/20211018220418/https://www.wired.com/story/hyperloop-south-korea/ |url-status=live}}</ref>{{update after|2018}} But theThe project was shelved in early 2024 after the Korean government withdrew public funding overdue to questions over the venture's economic viability.<ref>{{cite news |url=https://www.chosun.com/english/national-en/2024/03/19/33ACLJSONFDPDJJMJ4JVFTPIVE/#:~:text |title=A%20researcher%20said%2C%20%E2%80%9CPointing%20out,%E2%80%9Chigh%20uncertainty%20and%20riskS.%E2%80%9D Korea ends Seoul-Busan dream train research over profit concerns, while China advances |first1=Jong-hyun |last1=Lee |first2=Hyun-a |last2=Yeom |work=The Chosun |___location=South Korea |date=2024-03-19 |access-date=2025-04-09}}</ref>
 
In April 2025, the government launched a research project to develop [[maglev]] propulsion technology for the Hypertube, a proposed next-generation high-speed train system, between Seoul and Busan.<ref>{{cite news |url=https://en.yna.co.kr/view/AEN20250409001800320 |title=S. Korea launches research on maglev propulsion tech for envisioned Hypertube train |first=Dong-woo |last=Chang |work=Yonhap News Agency |date=2025-04-09 |access-date=2025-04-09}}</ref>
China has been at the forefront of cutting edge research into ultra high-speed transport and has in the last decade spearheading the successful construction of China's [[high-speed rail]] network into the world's most expansive rapid transport system.
In July 2024, China Railway Engineering Consulting Group ([[China Railway Group Limited|CREC]]) constructed a record-breaking 2 km long Maglev hyperloop test line in Yanggao County, [[Shanxi province]]. Using innovative techniques such as composite N-shaped beams incorporating steel shells and vacuum-sealed concrete, AI-driven magnetic damper and precision engineering afforded China the premiere opportunity to take the lead in the race to be the first country to commercialize a working hyperloop type of rapid transportation system. The spate of tests were conducted successfully with near-zero deviation from baseline indicating all design parameters have met expectation and CREC will proceed to expand the test line and scale up its production in order to finalized testing and develop various operation protocols to meet the challenges of large-scale deployment. Furthermore, unlike most current methodology used in various research test projects around the world, the highly advanced technology employed in the Chinese vacuum-tube test line and the capsule unit ensure scalability, maximum safety and ultimate comfort of the riders.<ref name="The-Star-March-2025">{{cite web |url=https://www.thestar.com.my/tech/tech-news/2025/03/20/how-china-is-solving-the-nightmare-that-killed-elon-musks-hyperloop |title=How China is solving the nightmare that killed Elon Musk’s Hyperloop |work=TheStar |first=Stephen |last=Chen |date=20 March 2025 |access-date=20 March 2025 |archive-date=20 March 2025 |archive-url=https://web.archive.org/web/20250320000000/https://www.thestar.com.my/tech/tech-news/2025/03/20/how-china-is-solving-the-nightmare-that-killed-elon-musks-hyperloop |url-status=live}} [https://www.msn.com/en-xl/news/other/how-china-is-solving-the-nightmare-that-killed-elon-musk-s-hyperloop/ar-AA1BhqT0#:~:text=China's%20solution%3A%20composite%20N%2Dshaped,shells%20and%20vacuum%2Dsealed%20concrete.&text=Inside%2C%20the%20team%20created%20a,by%20more%20than%20a%20third. Alt URL]</ref>
Currently, plans are in place to initiate a route between [[Shanghai]] and [[Beijing]] cutting travel time from 4 hours when utilizing high-speed bullet trains to under 90 minutes with the vacuum-tube transport traveling at {{cvt|1000|km/h|mph|round=50}}.<ref name="The-Star-March-2025"/>
 
==== United States ====
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In 2016, Canadian hyperloop firm [[TransPod]] explored the possibility of hyperloop routes which would connect [[Toronto]] and [[Montreal]],<ref name="cbc20160916">{{cite news |last=Bambury |first=Brent |date=16 September 2016 |title=Toronto to Montreal in less than 30 minutes? How a Canadian company plans to make it happen |work=[[CBC Radio]] |___location=Canada |url=http://www.cbc.ca/radio/day6/episode-303-charlie-sykes-on-nevertrump-predicting-the-polaris-climate-change-cities-plus-lots-more-1.3764152/toronto-to-montreal-in-less-than-30-minutes-how-a-canadian-company-plans-to-make-it-happen-1.3764201 |access-date=7 November 2016 |archive-date=9 May 2022 |archive-url=https://web.archive.org/web/20220509103644/https://www.cbc.ca/radio/day6/episode-303-charlie-sykes-on-nevertrump-predicting-the-polaris-climate-change-cities-plus-lots-more-1.3764152/toronto-to-montreal-in-less-than-30-minutes-how-a-canadian-company-plans-to-make-it-happen-1.3764201 |url-status=live}}</ref><ref name="Rapid Transit">{{cite news |date=18 September 2017 |title=Rapid Transit |publisher=CBC |agency=CBC |url=http://www.cbc.ca/news/business/rapid-transit-1.4296028 |access-date=4 October 2017 |archive-date=25 September 2017 |archive-url=https://web.archive.org/web/20170925053929/http://www.cbc.ca/news/business/rapid-transit-1.4296028 |url-status=live}}</ref> [[Toronto]] to [[Windsor, Ontario|Windsor]],<ref name="Daily Hive">{{cite news |last1=Aboelsaud |first1=Yasmin |date=26 July 2017 |title=Toronto tech company proposes Toronto-Windsor hyperloop connection |publisher=Daily Hive |url=http://dailyhive.com/toronto/transpod-hyperloop-study-toronto-windsor-2017 |access-date=4 October 2017 |archive-date=3 October 2017 |archive-url=https://web.archive.org/web/20171003050619/http://dailyhive.com/toronto/transpod-hyperloop-study-toronto-windsor-2017 |url-status=live}}</ref> and [[Calgary]] to [[Edmonton]].<ref name="cbccalgarycorridor">{{cite news |date=7 April 2017 |title=Calgary to Edmonton in 30 minutes? Hyperloop could be the future of transportation in Alberta |publisher=CBC |agency=CBC |url=https://www.cbc.ca/news/canada/calgary/transpod-hyperloop-calgary-edmonton-corridor-1.4060954 |access-date=4 October 2017 |archive-date=15 June 2022 |archive-url=https://web.archive.org/web/20220615010100/https://www.cbc.ca/news/canada/calgary/transpod-hyperloop-calgary-edmonton-corridor-1.4060954 |url-status=live}}</ref> Toronto and Montreal, the largest cities in [[Canada]], are connected by [[Ontario Highway 401]], the busiest highway in North America.<ref>{{cite web |date=6 April 2014 |title=The Busiest Highway in North America |url=http://oppositelock.kinja.com/the-busiest-highway-in-north-america-1559577839 |url-status=dead |archive-url=https://web.archive.org/web/20191112035613/https://oppositelock.kinja.com/the-busiest-highway-in-north-america-1559577839 |archive-date=12 November 2019 |access-date=7 November 2016 |work=Opposite Lock |___location=US}}</ref> In March 2019, Transport Canada commissioned a study of hyperloops, so it could be "better informed on the technical, operational, economic, safety, and regulatory aspects of the hyperloop and understand its construction requirements and commercial feasibility."<ref name="dh20190408">{{Cite web |last=Aboelsaud |first=Yasmin |date=4 April 2019 |title=Virgin Hyperloop One: New transit technology could be here in years not decades |url=https://dailyhive.com/toronto/virgin-hyperloop-one-transport-canada-april-2019 |access-date=8 April 2019 |website=Daily Hive |language=en |archive-date=11 April 2022 |archive-url=https://web.archive.org/web/20220411012020/https://dailyhive.com/toronto/virgin-hyperloop-one-transport-canada-april-2019 |url-status=live}}</ref>{{update after|2020}}
 
The province of [[Alberta]] signed a memorandum of understanding (MOU) to support [[TransPod]] for its [[Calgary]] to [[Edmonton]] hyperloop project. [[TransPod]] plans to move forward and has secured {{USD|550 million|long=yes}} in private capital funding for the first phase, which will create an airport link for [[Edmonton]].{{Clarify|date=May 2025|reason=There are already public transit links to Edmonton International Airport}} However, the company will first need to build and test prototypes on test tracks before the project can begin.<ref name=gnews20221021>{{cite web |title=$550M secured to help finance ultra-high-speed hyperloop between Edmonton and Calgary {{!}} Globalnews.ca |url=https://globalnews.ca/news/8718640/alberta-ultra-high-speed-hyperloop-edmonton-calgary-funding/ |access-date=2022-10-21 |website=Global News |language=en-US |archive-date=21 October 2022 |archive-url=https://web.archive.org/web/20221021025704/https://globalnews.ca/news/8718640/alberta-ultra-high-speed-hyperloop-edmonton-calgary-funding/ |url-status=live}}</ref><ref name=cbc20221020>{{cite web |last=Edwardson |first=Lucie |date=2021-06-25 |title=Canadian hyperloop company says ultra-high-speed travel between Calgary and Edmonton is feasible |url=https://www.cbc.ca/news/canada/calgary/transpod-hyperloop-calgary-edmonton-sebastian-gendro-1.6078775 |access-date=2022-10-20 |website=CBC News |archive-date=21 October 2022 |archive-url=https://web.archive.org/web/20221021025703/https://www.cbc.ca/news/canada/calgary/transpod-hyperloop-calgary-edmonton-sebastian-gendro-1.6078775 |url-status=live}}</ref>{{update after|2023}}
 
==== Elsewhere in the world ====
Line 138 ⟶ 101:
 
In 2017, [[SINTEF]], the largest independent research organization in Scandinavia, indicated they were considering building a test lab for hyperloop in Norway.<ref name=dnno20171218>{{cite news |url=https://www.dn.no/nyheter/2017/12/18/0648/Havbruk/sintef-vil-teste-hyperloop-for-laks |title=Sintef vil teste hyperloop for laks |trans-title=Sintef will test the hyperloop for salmon |work=Dagens Næringsliv AS |___location=Norway |date=18 December 2017 |access-date=23 January 2018 |language=no |archive-date=23 July 2018 |archive-url=https://web.archive.org/web/20180723071504/https://www.dn.no/nyheter/2017/12/18/0648/Havbruk/sintef-vil-teste-hyperloop-for-laks |url-status=live}}</ref>{{update after|2018}}
 
An agreement was signed in June 2017 to co-develop a hyperloop line between [[Seoul]] and [[Busan]], South Korea.<ref name=imeche20170719>{{cite news |url=http://www.imeche.org/news/news-article/investment-in-hyperloop-routes-speeds-up |title=Investment in hyperloop routes speeds up |first=Jørn |last=Madslien |publisher=Institute of Mechanical Engineers |___location=UK |date=19 July 2017 |access-date=11 August 2017 |archive-date=25 May 2021 |archive-url=https://web.archive.org/web/20210525055436/https://www.imeche.org/news/news-article/investment-in-hyperloop-routes-speeds-up |url-status=live}}</ref><ref name=wired20170620>{{cite magazine |url=https://www.wired.com/story/hyperloop-south-korea/ |title=South Korea Is Building a Hyperloop |first=Alex |last=Davies |magazine=Wired |___location=US |date=20 June 2017 |access-date=16 March 2019 |archive-date=18 October 2021 |archive-url=https://web.archive.org/web/20211018220418/https://www.wired.com/story/hyperloop-south-korea/ |url-status=live}}</ref>{{update after|2018}} But the project was shelved after the Korean government withdrew public funding over questions over the venture's viability.<ref>https://www.chosun.com/english/national-en/2024/03/19/33ACLJSONFDPDJJMJ4JVFTPIVE/#:~:text=A%20researcher%20said%2C%20%E2%80%9CPointing%20out,%E2%80%9Chigh%20uncertainty%20and%20risk.%E2%80%9D</ref>
 
====Mars====
Line 202 ⟶ 163:
 
=== Design and safety ===
YouTube creator Adam Kovacs has described Hyperloop as a kind of [[gadgetbahn]] because it would be an expensive, unproven system that is no better than existing technologies such as traditional high-speed rail.<ref>{{Citecite news |last1=Kovacs |first1=Adam |last2=Westbrook |first2=Adam |date=2022-10-13 October 2022 |title=Opinion {{!}} Elon Musk Has Some Bad Ideas for Mass Transit. We Have Solutions. |url=https://www.nytimes.com/2022/10/13/opinion/elon-musk-boring-loop.html |url-status=live |archive-url=https://web.archive.org/web/20230206171856/https://www.nytimes.com/2022/10/13/opinion/elon-musk-boring-loop.html |archive-date=6 February 2023 |access-date=2023-02-0626 May 2025 |work=The New York Times |language=en-US |issn=0362-4331}}</ref> John Hansman, professor of aeronautics and astronautics at [[Massachusetts Institute of Technology|MIT]], has pointed out potential design problems, such as how a slight misalignment in the tube would be compensated for, and the potential interplay between the air cushion and the low-pressure air. He has also questioned what would happen if the power were to go out when the pod was miles away from a city. [[University of California, Berkeley|UC Berkeley]] physics professor Richard Muller has also expressed concern regarding "[the Hyperloop's] novelty and the vulnerability of its tubes, [which] would be a tempting target for terrorists", and that the system could be disrupted by everyday dirt and grime.<ref name="Mercury-2016-09-16">{{cite news |url=http://www.mercurynews.com/2013/08/13/wolverton-elon-musks-hyperloop-hype-ignores-practical-problems/ |title=Wolverton: Elon Musk's Hyperloop hype ignores practical problems |last=Wolverton |first=Troy |date=16 September 2016 |orig-date=first published 13 August 2013 |work=The Mercury News |access-date=1526 SeptemberMay 2025 2016|archive-date=21 September 2016 |archive-url=https://web.archive.org/web/20160921080913/http://www.mercurynews.com/2013/08/13/wolverton-elon-musks-hyperloop-hype-ignores-practical-problems/ |url-status=live }}</ref>
 
The solarfeasibility panelsof Musk's plans to install alongpower the lengthhyperloop ofsystem thewith hyperloopsolar systempanels installed along its length havehas been criticizedquestioned by maglev train expert and engineering professor Roger Goodall of [[Loughborough University]],. as not being feasible enough to return enough energy to power the hyperloop system,Goodall arguingsaid that the air pumps and propulsion would requireprobably need much more power than the solar panels could generate.<ref name="Mercury-2016-09-16" />
 
=== Costs ===
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|U.S.
|2016
|Defunct (2018)<ref>{{Cite web|last=O'Kane|first=Sean|date=December 14, 2018|title=Hyperloop startup Arrivo is shutting down as workers are laid off|url=https://www.theverge.com/2018/12/14/18128848/hyperloop-arrivo-furloughs-layoffs-money-trouble|url-status=live|website=[[The Verge]]|access-date=25 March 2019|archive-date=25 March 2019|archive-url=https://web.archive.org/web/20190325075632/https://www.theverge.com/2018/12/14/18128848/hyperloop-arrivo-furloughs-layoffs-money-trouble}}</ref>
|Ended hyperloop development in November 2017 in favor of [[maglev]] transportation. Shut down in 2018.
|-
|[[DGWHyperloop]]
|India
|2015
|Active
|<ref>{{cite web |title=DGWHyperloop - India's Own Hyperloop |url=https://www.dgwhyperloop.in/ |website=www.dgwhyperloop.in |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-
|Hardt Hyperloop
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|2016
|Active
|<ref>{{cite web |title=Hardt Hyperloop |url=https://www.hardt.global/ |website=Hardt Hyperloop |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-
|Hyperloop Italia
Line 252 ⟶ 213:
|2020
|Active
||Subsidiary of [[Hyperloop Transportation Technologies]]<ref>{{cite web |title=Hyperloop Italia - Una nuova frontiera per la mobilità |url=https://hyperloopitalia.com/ |website=Hyperloop Italia |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-style="background-color:#CCC;
|[[Hyperloop One]]
Line 258 ⟶ 219:
|2014
|Shut down (2023)
|Ended development of passenger travel in February 2022 to focus on freight.<ref>{{cite news |url=https://www.businessinsider.com/virgin-hyperloop-layoffs-passenger-travel-cargo-transport-2022-2 |title=Virgin Hyperloop lays off half of its employees as it pivots away from passenger travel |first=Yoonji |last=Han |work=Business Insider |___location=US |date=22 February 2022 |access-date=6 May 2022 |archive-date=20 May 2022 |archive-url=https://web.archive.org/web/20220520091152/https://www.businessinsider.com/virgin-hyperloop-layoffs-passenger-travel-cargo-transport-2022-2 |url-status=live}}</ref> Shut down in December 2023.<ref>{{cite news |last=O'Kane |first=Sean |date=21 December 2023 |title=Hyperloop One is reportedly shutting down |website=TechCrunch |language=en-US |url=https://techcrunch.com/2023/12/21/hyperloop-one-shutting-down/ |access-date=14 August 2025}}</ref>
|-
|[[Hyperloop Transportation Technologies]]
Line 264 ⟶ 225:
|2013
|Active
|<ref>{{cite web |title=Hyperloop Transportation Technologies |url=https://www.hyperlooptt.com/ |website=HyperloopTT |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-style="background-color:#CCC;
|[[Nevomo]]
Line 276 ⟶ 237:
|2019
|Active
||<ref>{{cite web |title=Swisspod Our Story |url=https://www.swisspod.com/our-journey |website=www.swisspod.com |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-
|[[TransPod]]
Line 282 ⟶ 243:
|2015
|Active
|<ref>{{cite web |title=Homepage |url=https://www.transpod.com/ |website=TransPod |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-
|Zeleros
Line 288 ⟶ 249:
|2016
|Active
||<ref>{{cite web |title=Zeleros Hyperloop - Welcome to the future of transportation |url=https://zeleros.com/ |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|-
|TuTr Hyperloop
|India
|2022
|Active
||<ref>{{cite web |title=TuTr Hyperloop - Welcome to the TuTr Hyperloop |url=https://tutr.tech/ |access-date=11 February 2024}}</ref>{{primary inline|date=August 2025}}
|}
 
Line 300 ⟶ 267:
* [[Swissmetro]] was a proposal to run a maglev train in a low-pressure environment. Concessions were granted to Swissmetro in the early 2000s to connect the Swiss cities of St. Gallen, Zurich, Basel, and Geneva. Studies of commercial feasibility reached differing conclusions and the vactrain was never built.<ref name="swissmetro"/>
* [[ET3 Global Alliance]] (ET3) was founded by Daryl Oster in 1997 with the goal of establishing a global transportation system using passenger capsules in frictionless [[magnetic levitation|maglev]] full-vacuum tubes. Oster received interest from Elon Musk potentially investing in a {{convert|3|mi|km|0|adj=on}} prototype of ET3's proposed design.<ref name="denver20130809"/><ref name="futurist20131030"/>{{update after|2015|6|17}}
* In 2003 [[Franco Cotana]] led the development of Pipenet, with a {{convert|100|m|yd|abbr=on}}|adj=mid|-long}} {{convert|1.25|m|yd|abbr=on|adj=mid|-diameter}} diameter prototype system constructed in Italy in 2005, with a vision to use an evacuated tube for moving freight at up to {{convert|2000|kph|mph|abbr=on}} using linear synchronous motors and magnetic levitation. However development stopped after funding ceased.<ref>{{cite web |title=The Hyperloop that never was |date=5 May 2021 |url=https://sifted.eu/articles/italy-deeptech-pipenet/ |publisher=Sifted |access-date=2021-08-26 |archive-url=https://web.archive.org/web/20210505172003/https://sifted.eu/articles/italy-deeptech-pipenet/ |archive-date=2021-05-05}}</ref>
* In August 2010, a vacuum-based maglev train able to move at {{convert|1000|km/h|mph|abbr=on|order=flip|round=50}} was proposed for China, projected to cost {{CNY|10–20 million|link=yes}} ({{US$|2.95 million}} at the August 2010 exchange rate) more per kilometer than regular high-speed rail.<ref name="engadgetsumohurd20100804"/> In 2018, a short {{convert|45|m|yd|abbr=on}} loop test track was completed to test some parts of the technology.<ref>{{cite news |title=China testing super-maglev train that runs at 1,000 km/h |url=http://en.people.cn/n3/2018/0311/c90000-9435653.html |access-date=2021-08-26 |publisher=People's Daily Online |date=11 March 2018 |archive-date=24 October 2021 |archive-url=https://web.archive.org/web/20211024003226/http://en.people.cn/n3/2018/0311/c90000-9435653.html |url-status=live}}</ref>
 
Line 317 ⟶ 284:
* [[Gravity train]]
* [[Gravity-vacuum transit]]
* [[Ground -effect train]]
* [[High-speed rail]]
* [[Kantrowitz limit]]
Line 366 ⟶ 333:
<!--<ref name="gizmag 201502">{{cite news |url=http://www.gizmag.com/agreement-reached-to-build-first-passenger-hyperloop/36285 |title=California is getting a Hyperloop, but not where you think |work=Gizmag |first=Eric |last=Mack |date=26 February 2015 |access-date=2 March 2015}}</ref>-->
 
<ref name="nova20130813">{{cite news |url=https://www.pbs.org/wgbh/nova/next/techarticle/hyperloop-and-high-speed-trains/ |title=Promise and Perils of Hyperloop and Other High-Speed Trains |series=[[Nova (American TV series)|Nova Next]] |work=PBS.org |first=Tim |last=De Chant |date=13 August 2013 |access-date=24 September 2013 |archive-date=14 September 2018 |archive-url=https://web.archive.org/web/20180914132501/http://www.pbs.org/wgbh/nova/next/tech/hyperloop-and-high-speed-trains/ |url-status=live}}</ref>
 
<!--<ref name="BizWeek">{{cite web |url=http://www.businessweek.com/articles/2013-08-12/revealed-elon-musk-explains-the-hyperloop |archive-url=https://web.archive.org/web/20130813011222/http://www.businessweek.com/articles/2013-08-12/revealed-elon-musk-explains-the-hyperloop |url-status=dead |archive-date=13 August 2013 |title=Revealed: Elon Musk Explains the Hyperloop, the Solar-Powered High-Speed Future of Inter-City Transportation |last=Vance |first=Ashlee |date=13 August 2013 |work=Bloomberg Businessweek |access-date=13 August 2013}}</ref>-->
Line 418 ⟶ 385:
<ref name="WaPoWonkBlog">{{cite news |url=https://www.washingtonpost.com/blogs/wonkblog/wp/2013/08/13/there-is-no-redeeming-feature-of-the-hyperloop/ |title=There is no redeeming feature of the Hyperloop |newspaper=[[The Washington Post]] |first=Brad |last=Plumer |date=13 August 2013 |access-date=31 August 2017 |archive-date=12 November 2013 |archive-url=https://web.archive.org/web/20131112063604/http://www.washingtonpost.com/blogs/wonkblog/wp/2013/08/13/there-is-no-redeeming-feature-of-the-hyperloop/ |url-status=live}}</ref>
 
<ref name="economist20130817">{{cite news |url=https://www.economist.com/news/science-and-technology/21583588-elon-musk-electric-car-entrepreneur-and-proponent-private-colonies-mars |title=The Future of Transport: No loopy idea |newspaper=The Economist |volume=Print edition |date=17 August 2013 |access-date=16 August 2013 |url-access=limited |archive-date=5 March 2016 |archive-url=https://web.archive.org/web/20160305004626/http://www.economist.com/news/science-and-technology/21583588-elon-musk-electric-car-entrepreneur-and-proponent-private-colonies-mars |url-status=live}}</ref>
 
<ref name="business20130715">{{cite news |url=http://www.businessinsider.com/elon-musks-hyperloop-science-fiction-2013-7 |title=If Elon Musk's Hyperloop Sounds Like Something Out Of Science Fiction, That's Because It Is |work=[[Business Insider]] |first=Chris C. |last=Anderson |date=15 July 2013 |access-date=14 August 2013 |archive-date=9 August 2013 |archive-url=https://web.archive.org/web/20130809060249/http://www.businessinsider.com/elon-musks-hyperloop-science-fiction-2013-7 |url-status=live}}</ref>