Report: The Future of Hyperloop

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All common modes of passenger transportation show an increase in demand, leading to a growth in problems: capacity shortage, environmental pollution and disruptive situations. A promising solution for these problems is the hyperloop: a high-speed transportation system using near vacuum tubes in which pressurised vehicles travel. This report, commissioned by the Dutch Ministry of Infrastructure and Water Management, provides an update on hyperloop development. The main goal of this report is to give an objective overview of hyperloop knowledge, in order to accelerate the realisation of a hyperloop. Furthermore, recommendations are giving to the Ministry of Infrastructure and Water Management. At the time of publishing, multiple student teams, companies and non-profit organisations are working to realise a hyperloop. However, they have different visions of a hyperloop system and convergence towards certain technologies or parameters is yet to be reached.

Technology

Multiple technologies have potential for a hyperloop, and additional research and development has to be conducted to determine the most feasible technologies. Delft Hyperloop has researched several subsystems, and based on this research, recommendations are given.

Levitation: Electrodynamic Suspension (EDS) and Electromagnetic Suspension (EMS) are the two most promising technologies for levitation, as they are currently used in Maglev trains. For the operational speeds of a hyperloop, both technologies still need to be proven. EMS is very promising because of its low energy consumption. However, as the system needs an active control system to levitate, it is less reliable from a safety point of view. EDS, which is a fail-safe passive levitation method with relatively large air gaps, is therefore opted for as the most promising levitation option as safety is an important design criteria. 

Propulsion: A Linear Synchronous Motor (LSM) and a Linear Induction Motor (LIM) are the two most promising technologies for propulsion. A LIM performs best in terms of costs and reliability, however current technology is not able to reach the same speed as an LSM. Furthermore, LSM is the best option regarding energy consumption. During further development, the reliability and safety of an LSM should be increased.

Passenger Pod: Although the near vacuum environment, passenger pod design should take aerodynamically optimised shapes into account to minimise aerodynamic drag. The capacity of a pod is recommended to be around 50, to cope with the expected demand in a European network. Based on aircraft design guidelines, a pod diameter of 2.7 m is recommended to fit three seats abreast, including an aisle. This includes 0.2 m for structural components including isolation. Furthermore, to diminish station size, it is recommended to have a bidirectional pod.

Tube: With a blockage ratio of 0.7, the tube diameter becomes 3.5 m. Steel is recommended as material, however it is useful to closely pay attention to new technological developments of other materials. Developments to watch are steel weight optimisations and fibre reinforced polymers. If additional aesthetic value is needed, acrylic transparent tubes might be suitable, although expensive. A steel tube thickness of 25 mm is advised to withstand vacuum buckling, including a safety factor. More extensive calculations are needed for the final design of the tube.

Vacuum: The optimal tube pressure depends on the pod frequency in the tube: the more pods in the tubes, the more efficiency is gained when the pressure is lower, because all pods will experience a reduced aerodynamic drag and therefore reduced power consumption. For a frequency of 2 pods per minute, the optimal tube pressure is 3 Pa, under the assumption that the pumping speed and the power required per vacuum pump do not vary with pressure. It is advised to have a variable tube pressure, that varies dependent on the changing pod frequency.

Communication: Current communication technologies used in high-speed railways are not suited for hyperloop speeds. The main challenge lies within the communication from the pod to the outside world, which is necessary to exchange data. Optical fibre is a technology that has potential to solve this challenge. Furthermore, there is a possibility that new communication protocols get developed in the coming years, such as 5G. This would erase the need for current technologies in a hyperloop system. However, as the development of new technologies is uncertain, it is useful to further develop current technologies in order to make them suitable for high-speed transportation.

Artificial Intelligence: Application of Artificial Intelligence is promising for the hyperloop. This can be used during designing, building, operating and maintaining the system. For example incident detection, ensuring on-board safety and prediction of (sub)system failure, can be areas where Artificial Intelligence can be applied. Next to that, it can be used for optimising security checks, timetables and scheduling.

Impact of a Hyperloop

A European hyperloop network designed by Delft Hyperloop, is able to transport over 300 million passengers yearly by replacing a share of the short-haul air passenger transportation. The network connects 48 of the largest cities in Europe and can take over two-thirds of all passengers flying between these cities. By doing so, the environmental impact of transportation will be diminished, as a hyperloop is fully electric. It is estimated that the hyperloop infrastructure costs approximately “38 million per kilometre above-ground, and “61 million per kilometre underground. This means that the complete designed network, which requires 19.700 km of bidirectional tube, would cost close to a trillion euro. Next to providing high-speed transportation, a hyperloop network will positively impact society. By increasing the connectivity between cities, welfare will be enlarged.

Safety

Safety is the most important aspect of a hyperloop system. To increase passenger safety, hazard mitigation methods need to be incorporated during design. It is important to maintain and monitor all subsystems thoroughly to ensure a reduced likelihood for failures. Furthermore, a redundant power supply system is desired to ensure safe operation in case of a power outage. As communication is one of the most critical subsystems, it is advised to incorporate a secondary communication system. Next to that, the tube is the most sensitive subsystem for black-swan risks: risks with a low likelihood and severe consequences. 

To guarantee safety, it is important to test all subsystems thoroughly, which shows the need for a test facility where pods can reach speeds over 1000 km/h. A high-speed test facility is also necessary for certification purposes. For this certification, it is advised to found an agency that is responsible for hyperloop certification. Multiple stakeholders should be involved in this agency. 

To minimise the cost for emergency exits, while still guaranteeing safety, it is recommended to further investigate the potential of Safe Havens. Safe Havens are intermediate emergency exit stations, where pods can stop to provide safe exit to the passengers. Whilst doing so, impact on the operation of the rest of the system is minimised.

Challenges

Hyperloop is a promising innovation in order to decrease the rising problems in transportation, however there are still various challenges. To increase interoperability, it is important that there will be a single European standard. However, it is necessary that this does not happen too early in the process, as multiple techniques have to be developed first in order to research their potentials. To accelerate development of these techniques, policy support for infrastructure is essential. Standardisation is hard to achieve, as it is difficult to converge to an optimal system. Furthermore, similar to existing infrastructure, hyperloop infrastructure is expensive. It is nearly impossible to find a single party that is able to finance the construction of a complete European network, which is why a public-private partnership is most likely needed. However, as governments will be involved, political aspects will make this more complex. Finally, high-speed switches are essential for realising efficient point-to-point connections. However, as these switches do not yet exist, these need to be developed.

Conclusions

The hyperloop provides a sustainable solution to the growing demand for high speed travel within Europe. In order to successfully realise a hyperloop system, two main focus points can be identified: working towards standardisation and setting up the foundation for implementation. It is recommended to start setting up a framework for standardisation in the future. The three main steps will be continuing research and development, sharing knowledge and investing in a long test track. Planning for actual implementation should already start in the early phases of the project in order to create maximum benefit for future passengers and European citizens in general. The three main steps will be to found a European agency for certification, secure financing and determine the location of the first links.

By Delft Hyperloop, June 2019