Putting Maglev on Track' (Issues, Spring 1990) observed that growing airline traffic and associated delays were already significant and predicted that they would worsen. The article argued that a 300-mile-per-hour (mph) magnetic levitation (maglev) system integrated into airport and airline operations could be a part of the solution. Maglev was not ready for prime time in 1990, but it is now.

This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents both measured and calculated magnetic-force data. Because dynamic instability is not acceptable for any commercial maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments on maglev systems and compares the results with predictions calculated by a nonlinear-dynamics computer code. Instabilities of an electrodynamic-suspension system type vehicle model were obtained by experimental observation and computer simulation of a five-degree-of-freedom maglev vehicle moving on a guideway that consists of a pair of L-shaped aluminum conductors attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of maglev systems.

There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped. Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.

Limitations on the use of petroleum-based diesel fuel in California could occur pursuant to declaration by the California Air Resources Board (CARB) that the particulate matter component of diesel exhaust is a toxic air contaminant subject to the state’s Proposition 65. It is the declared intention of CARB not to ban diesel fuel, per se, at this time. Assuming no total ban, Argonne National Laboratory (ANL) explored two feasible “midcourse” strategies that result in some degree of (conventional) diesel displacement. In the first case, substantial displacement of compression-ignition (CI) by spark-ignition engines occurs and diesel fuel remains admissible for ignition assistance as a pilot fuel in natural gas–powered heavy-duty vehicles. Daily gasoline demand in California increases by 32.2 million L (8.5 million gal) overall, about 21 percent above the 2010 baseline demand projected by California’s energy and environmental agencies. Daily natural gas demand increases by 13.6 million diesel L (3.6 million gal) equivalents, about 7 percent above projected (total) consumption level. In the second case, CI engines utilize substitutes having similar ignition and performance properties for petroleum-based diesel. For each case, ANL estimated localized air emission plus generalized greenhouse gas and energy changes. Fuel replacement by dimethyl ether yields the greatest overall reduction in nitrogen oxide emissions. All scenarios bring about fine particulate matter (PM10) reductions relative to the 2010 baseline, with greatest reductions from the CI-displacement case and the least from fuel replacement by Fischer-Tropsch synthetic diesel. Institutional and cost implications of vehicle and engine replacement were not formally evaluated.

The paper discusses alternatives to diesel displacement, describing several scenarios. It studies three basic cases: (1) cars and trucks; (2) urban buses; and (3) off-road vehicles. The discussion also includes changes in energy use and emissions expected from the production and combustion of alternative fuels.

This paper compares the two modes of transportation, and notes important similarities and differences in the technologies and in how they can be implemented to their best advantage. Problems with making fair comparisons of the costs and benefits are discussed and cost breakdowns based on data reported in the literature are presented and discussed in detail. Cost data from proposed and actual construction projects around the world are summarized and discussed. Results from the National Maglev Initiative and the recently-published Commercial Feasibility Study are included in the discussion. Finally, estimates will be given of the expected cost differences between HSR and maglev systems implemented under simple and complex terrain conditions. The extent to which the added benefits of maglev technology offset the added costs is examined.

Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.

Because dynamic instabilities are not acceptable in any commercial maglev system, it is important to consider dynamic instability in the development of all maglev systems. This study considers the stability of maglev systems based on mathematical models and experimental data. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis for motion-dependent magnetic-force-induced instability developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.

The importance of vehicle/guideway dynamics in maglev systems is discussed. The particular interests associated with modeling vehicle/guideway interactions and explaining response characteristics of maglev systems for a multicar, multiload vehicle traversing on a single- or double-span flexible guideway are considered, with an emphasis on vehicle/guideway coupling effects, comparison of concentrated and distributed loads, and ride comfort. Coupled effects of vehicle/guideway interactions over a wide range of vehicle speeds with various vehicle and guideway parameters are investigated, and appropriate criteria for decoupling at critical vehicle speeds or crossing frequencies are identified.

An analysis of a Japanese Maglev system that uses only one set of coils in the guideway for combined levitation, propulsion, and guidance functions is presented. This preliminary study, using the dynamic circuit approach, indicates that the system is very promising.<>

This report discusses the computer modeling and experimental verification of the magnetic forces associated with a figure-eight-shaped null-flux coil suspension system. A set of computer codes called COILGDWY, were developed on the basis of the dynamic circuit model and verified by means of a laboratory model. The experimental verification was conducted with a rotating PVC drum, the surface of which held various types of figure-eight-shaped null-flux coils that interacted with a stationary permanent magnet. The transient and dynamic magnetic forces between the stationary magnet and the rotating conducting coils were measured and compared with results obtained from the computer model. Good agreement between the experimental results and computer simulations was obtained. The computer model can also be used to calculate magnetic forces in a large-scale magnetic-levitation system.

Measurements were made of the forces experienced by two narrow but relatively long permanent magnets positioned above a moving, electrically conducting surface. The intent was to determine the accuracy of various means of computing these forces. It was found that the behavior at very high speeds can be approximated by using elementary methods and making the assumption that magnetic images are formed in the conductor. At lower speeds, a published formulation that uses Fourier transform techniques is quite reliable for the parameters of the experiments. A commercial computer code that uses a finite-element method of analysis is also in good agreement The results are relevant to the design of high-speed magnetically levitated (maglev) ground transportation vehicles having multiple magnets, where the guideway consists of a continuous-sheet conductor.

Dynamic interactions between the vehicle and guideway of a high speed ground transportation system based on magnetically levitated (maglev) vehicles were studied, with an emphasis on the effects of vehicle and guideway parameters. Two dynamic models for the vehicle are presented. In one model, the vehicle is considered a moving force travelling at various speeds on a simply supported single- or two-span beam(s). In the second model, the vehicle is considered to be one-dimensional, with two degrees of freedom, representing the primary and secondary suspensions of the vehicle with lumped masses, linear springs, and dampings. The Bernoulli-Euler beam equation is used to model the characteristics of a flexible guideway, and the guideway synthesis is based on a modal analysis method. Analyses have been performed to understand response characteristics under various loading conditions, and provide some benchmark data for verification of existing comprehensive computer programs and some basic design guidelines for maglev systems.