TECHNICAL ARTICLE AS PUBLISHED IN The Journal October 2018 Volume 136 Part 4 If you would like to reproduce this article, please contact: Alison Stansfield MARKETING DIRECTOR Permanent Way Institution [email protected] PLEASE NOTE THE OPINIONS EXPRESSED IN THIS JOURNAL ARE NOT NECESSARILY THOSE OF THE EDITOR OR OF THE INSTITUTION AS A BODY. TECHNICAL HSGT Systems: AUTHOR: Manuel Contreras HSR, Maglev and Stanway Consulting Hyperloop INTRODUCTION However, they all have a potential operational force is generated producing the levitation speed in excess of 218mph, see table 1. of the train. Sensors in the train regulate the The need for high speed transportation current in the coils, maintaining a 1cm gap from systems has intensified in recent decades. HIGH-SPEED RAIL (WHEEL-RAIL) the guideway. Electromagnets placed on both All industrialised countries have faced two L-shaped arms of the train are responsible for serious transportation problems in urbanised High-speed rail (HSR) is a type of rail the centering of the train on the track. regions and in major intercity corridors; Firstly, transport that operates significantly faster highway and street congestion, causing long than traditional rail traffic, using an integrated DISADVANTAGES travel times, economic inefficiencies, and system of specialised rolling stock and deterioration of the environment and quality dedicated tracks. There is no single standard Dynamic Instability: Magnetic attraction varies of life. Secondly, rising congestion at airports, that applies worldwide, but new lines in excess inversely with the cube of distance, so minor with similar social and economic costs. of 250 km/h (160 mph) and existing lines in changes in the magnets and the rail produce excess of 200 km/h (124 mph) are considered greatly varying forces. These changes in force High-Speed Ground Transportation systems to be high-speed, with some extending are dynamically unstable; a slight divergence (HSGT) is one way to address these issues, the definition to include lower speeds in from the optimum position tends to increase, improve connectivity, encourage development, areas for which these speeds still represent requiring sophisticated feedback systems to enhance business opportunities and provide an significant improvements. High-speed trains maintain a constant distance from the track. alternative transportation mode. This concept normally operate on standard gauge tracks of emerged as the inclusion of two systems; high- continuously welded rail on grade-separated High precision required in the construction of speed railways (HSR) and magnetic levitation right-of-way that incorporates a large turning the guideway. trains (Maglev). radius in its design. Susceptible to earthquakes. Both HSR and Maglev, are physically guided LINES IN OPERATION systems on fully controlled ways with fail-safe MAJOR ADVANTAGES OVER EDS electronic signal control. This provides not 29,792km of High Speed lines in the world only an order of magnitude of high safety (1 April 2015) The EMS system works at all speeds and but also reliable operation even under eliminates the need for a separate low-speed capacity conditions and a reduction in carbon MAGNETIC LEVITATION suspension system, simplifying the track layout. emissions. In addition to these systems, Elon (MAGLEV) Musk, CEO at Space X and Tesla, announced a new fixed-guideway intercity transport mode ELECTRODYNAMIC SUSPENSION SYSTEM The Maglev system consists of four main called Hyperloop in 2013. (EDS) components: guideway, vehicle, power supply and operation control system. Maglev HSGT is an efficient means for transporting The EDS system is based on vehicles use noncontact magnetic levitation, large passenger volumes with high speed, superconductivity, which is a quantum guidance and propulsion systems and have no reliability, passenger comfort, and safety. mechanical phenomenon of the exact zero wheels, axles and transmission. The common electrical resistance and repulsion of magnetic point in all applications is the lack of contact Any proposal for the introduction of a new fields (Meissner Effect), occurring in certain and therefore there is no wear and friction. transportation mode requires a complete materials, called superconductors, when This increases energy efficiency, reduces analysis that should address among others the cooled (e.g: liquid nitrogen, liquid helium) below maintenance costs, and increases the useful questions in image 1. a characteristic critical temperature (T<Tc) see life of the system. image 2. This White Paper provides a technical overview Maglev systems are divided into two groups: of the three current guided systems, which are The levitating force is generated between Electromagnetic Suspension (EMS) and based on different concepts, technologies at superconducting magnets on the trains and Electrodynamic Suspension (EDS). different levels of development, acceptance, coils on the track. applications as well as present and future Magnetic coils are used both for levitation ELECTROMAGNETIC SUSPENSION challenges. and propulsion. Trains are accelerated by SYSTEM (EMS) alternating currents on the ground producing attraction and repulsion forces with the TECHNOLOGY OVERVIEW In EMS systems, the guideway possesses a superconductors on the train. The levitation ferromagnetic material that has no permanent and guidance system, working with the same The following transportation systems are magnetism and the train incorporates some principle, ensures that the train is elevated and at different stages of development and the electromagnets that are oriented towards the centred in the track. See image 3. technologies are substantially different. rail from below. When the electromagnets of the vehicle are put into operation, an attraction 29 TECHNICAL Image 1 Table 1: Overview of HSR, Maglev and Hyperloop systems Image 2: B = Magnetic field. Diagram of the Meissner Effect Image 3: Electrodynamic suspension system (EDS) DISADVANTAGES INDUCTRACK (PASSIVE MAGLEV) HYPERLOOP Inductrack is an EDS system that uses Need for a separate low-speed suspension unpowered loops of wire in the track and Hyperloop is a concept and proposed system: Due to the train requiring wheels to permanent magnets on the vehicle. The transportation system for passenger and/ support the train until it reaches levitating magnets, which are required to produce the or freight using magnetic propulsion to carry speed, the entire track must be able to support necessary magnetic fields instead of using vehicles/pods through partial-vacuum tubes to both low- and high-speed operation. electromagnets or superconducting magnets, offer high speed inter-city transport. The main are arranged into a so-called Halbach array goal of the concept is to reduce air resistance MAJOR ADVANTAGES OVER EMS which concentrates the magnetic field intensity and friction to achieve very high speeds (near- below the array and cancels out above it. sonic speeds over 760 mph; 1,100 km/h) and Dynamic Stability: Changes in distance Additionally, the train has auxiliary wheels moderate energy consumption. between the track and the magnets create which can be used at lower speeds in case of strong forces to return the system to its original system failure, see table 4. position, see table 3. 30 TECHNICAL The main technologies used in Hyperloop are: CURRENT DEVELOPMENT AND Current railway research and development FUTURE CHALLENGES programs aim to achieve higher operational • Partial-vacuum tubes to reduce speeds combined with lower aerodynamic environmental pressure and air resistance resistance and new energy transmission HIGH-SPEED RAIL on pods. systems. In the coming years, high- speed rail will also make improvements in The first high speed rail began operations in • Passive magnetic levitation (Inductrack) standardisation and modularity of rolling Japan in 1964 (Shinkanshen – “Bullet Train”) to reduce friction of the vehicles. stock, new braking systems, improvements to and HSR lines have been in operation since make it more environmentally friendly (noise, then demonstrating excellent efficiency and • Linear induction motor (LIM) as a energy efficiency) and new technologies safety, attracting passengers and improving propulsion and braking system. (telecommunications, WI-FI, etc.) economic efficiency. Compatibility of the rail systems is fundamental for the creation of • Vehicles/pods to transport passengers MAGLEV an integrated international network of high and/or freight. speed ground transportation lines. Maximum Maglev is another technology for guided operating speed is the most important feature LINES IN OPERATION transportation systems with strong public of this system. appeal because of its unique feature: the • Two test tracks have been built to test the vehicles are supported, guided and propelled However, developments in high-speed rail have technology: by magnetic forces, so there is no physical historically been impeded by the difficulties contact between wheels and guideway in managing friction and air resistance, both • SpaceX’s test facility in California surfaces. Maglev systems can be considered of which become substantial when vehicles (1,25km) technically and operationally feasible and are approach high speeds. presumed to have certain advantages over • Hyperloop One’s “DevLoop,” in Nevada HSR. (500m)) Table 2. Comparison between EMS and EDS systems Table 3. Examples of Maglev Lines 31 TECHNICAL The two versions of this system, EMS and Another advantage is that noise generated