ADVANCED SYSTEMS a n d ADVANCED TECHNOLOGY A SUMMARY OF TEN YEARS OF ADVANCED RESEARCH AND DEVELOPMENT BY TH E FEDERAL RAILROAD ADMINISTRATION O c to b e r 1 , 1 9 7 7 Abstracted from Report FRA/ORD-7 7 / 2 7 by Office of Research and Development Federal Railroad Administration Department of Transportation Washington, D. C. 25 - Rsc D Management C o n t e n t s A d v a n c e d S y s t e m s Page Systems Engineering ........................ 1 Tracked Air Cushion Vehicles ......... 3 Component Research.............. 4 Tracked Levitated Research Vehicle..................................... 5 Prototype Tracked Air Cushion Vehicle...............-.................... 8 Magnetic Levitation....................... 10 Tube Vehicles .................................... 13 Multimodal........................................15 Suspended Vehicles ......................... 15 A d v a n c e d T e c h n o l o g y Page Linear Electric Motors ....................... 17 Linear Induction Motor Research Vehicle....................... 18 Mathematical Models................... 21 Single-sided Motors....................... 21 Guideways........................................22 Power Conditioning.........................23 Controls........................................... 26 Obstacle Detection...........................27 Communications.............................. 28 Appendix: Active FRA Programs a. Advanced Systems ....................... 29 A d v a n c e d S y s t e m s A question facing O H S G T in 1965 was: pose of extending the H S G T state-of-the- “H o w fast is high-speed ground transporta­ art review performed by MIT in 1965. The tion?” O H S G T researchers developed an systems engineers then derived a repre­ answer based on power requirements and sentative transportation system from each energy consumption. A plot of the power group, and m a d e detailed engineering required vs. speed for propulsion of various studies on them during the 1967-1971 vehicles in Figure 1 shows the region of 300 period. Those representatives were High m p h (483 km/h) was a reasonable range Speed Rail, Tube Vehicles, Suspended because power requirements above that Monorails, Dual Mo d e (includes automated limit increase to where increased fuel ex­ highways and combinations of high-speed penditure for marginal time savings make ground and automobile), and Tracked Air higher speeds unattractive, at least in open Cushion Vehicles. A R & D program on rail air. In evacuated tubes, the lower air pres­ components started at the beginning of the sure presents less drag, and speeds of 600 H S G T Program. While the rail systems en­ m p h (966 km/h) might be practical. gineering study did assist in pinpointing technical deficiencies requiring further R& D Systems Engineering for high speed passenger service, the cost and performance estimates provided to the OHSGT-sponsored studies focused the Northeast Corridor analyses were the major R & D on providing the best high-speed contribution. ground concepts as candidates in the Northeast Corridor Transportation Project MITRE and TR W analyses of Tube Vehicles cost-benefit comparisons. The comparisons found exceptionally high performance with sought to identify the best alternative for low expenditures of energy in partially improvement of passenger transportation in evacuated tubes. As the studies progressed, the corridor between Boston and Washing­ environmental and aesthetic considerations ton. The first objectives of the systems en­ pointed to the desirability of operating in gineering program were to predict perfor­ tunnels rather than in tubes on the surface. mance of the candidates and to identify Maintenance of low pressures could be rela­ deficiencies in the technology required to tively easy in hard rock tunnels. Tunneling achieve the predictions. costs however, would have to be drastically reduced before such systems will be eco­ T R W , Inc. assembled all known concepts nomically competitive. O n preliminary in­ for ne w H S G T systems and did in-depth vestigation, several proposed tunneling engineering analyses to determine those techniques appeared to hold promise of which were technically feasible. O H S G T such costs reductions, therefore, while a held discussions with some 200 different tunneling program endeavored to reduce organizations and individuals for the pur­ construction cost, the Tube Vehicle R & D 1 Tracked Air Cushion Vehicles on linear motor-propelled TACVs. After (TACV) laboratory tests on linear motors and air cushions, TH L built an unmanned test ve­ As noted in the Systems Engineering sec­ hicle and an elevated guideway. Tests were run for some months, but a change of gov­ tion, one of the technologies chosen for detailed systems analysis was TACV. A ernments in 1973 brought an end to fund­ ing. T A C V is supported and guided by cushions of air, formed by a flow of pressurized air Study of data obtained from Aerotrain and from on-board compressors and controlled Tracked Hovercraft led O H S G T to con­ by a small leakage gap between the vehicle clude that a large-scale research vehicle was and the guideway. The vehicle weight is practical and, in fact, was the only way to get distributed over a large area without contact the accurate performance and cost data and resulting friction. (See Figure 2 for needed to supplement the H S G T pro­ schematic representations of various air gram’s theoretical systems analyses. Small cushion designs.) TACVs evolved from development of marine air cushion vehicles (ACV) and their BASIC AIR CUSHION land-based versions, called Ground Effect SUSPENSION CONFIGURATIONS Machines. The British invented the marine FLOW A C V and later pursued development of T A C V s through the organization of Tracked Hovercraft Ltd. The French built the first large-scale TACV. The Societe d’ 7--------7---------7-------- 7-------- 7-------- 7-------- 7--------7---------7-------- 7--------- T Aerotrain built a half-scale propeller-driven PERIPHERAL JET SUSPENSION model and a 4.4-mile (7 km) test track in 1965. The half-scale vehicle made hun­ dreds of runs, carrying a crew of two and up FLOW to four passengers. These demonstrations gathered data on ride quality and aerodynamic forces. With rocket boosters and a jet engine substituted for the turbo prop engine, the Aerotrain reached speeds of up to 215 m p h (346 km/h). A second ROLLING FLEXIBLE BAG SUSPENSION Aerotrain, carrying 80 passengers on an 1 1 -mile (17 km) elevated guideway, went into operation in 1968. The 80-passenger FLOW vehicle ran a reliability test of 15,538 miles (25,000 km) with good performance. Aerotrain proposed several routes from Paris to nearby cities, but the French gov­ ernment did not provide the necessary ~l----------7---------- III---------- > / I T ■ I I funds. Testing continues with the vehicle and guideway, See Figure 3. FLEXIBLE BAG HINGED PAD SUSPENSION The British government, through Tracked Hovercraft Ltd. (THL), sponsored research Figure 2. Different Designs of Air Cushion 3 design is technically quite simple and could • dynamic response of vehicle and guide­ use the Tracked Levitated Research Vehicle way (TLRV) channel guideway or minor modifi­ • air cushion design, scale effects, and cations of it Figure 4 shows a ram air wearability cushion vehicle model on the Princeton guideway. The ducting around the fan • air supply systems along with the walls of the channel guide­ • aerodynamic performance and stability way provide sufficient attenuation of the propeller noise to overcome this objection • ride quality to a propeller. • secondary suspension requirements for passenger comfort In 1970, a formal exchange of information began with Tracked Hovercraft Ltd. (THL). • analytical models of the vehicle/ T H L studied: guideway system • costs of constructing the British, French, • linear induction motor performance and U.S. guideway designs; • high-speed power collection • air cushion power required to keep a ve­ Design of the T L R V involved much that was hicle stable in crosswinds; and unique— not only the vehicle and air cush­ • single-sided and double-sided linear ions but also the secondary suspension be­ motors for TA C V propulsion. tween the air cushion and the body, the second-generation linear motor propulsion, Tracked Levitated Research Vehi­ the on-board power conditioning unit, and cle. In March 1970, Gr u m m a n Aerospace the power collection equipment. In order to Corporation started design of an air cushion avoid development of electric air com­ research vehicle— first called the Tracked pressors— even though the technical risk Air Cushion Research Vehicle and, later, was known to be low— F R A selected aircraft the Tracked Levitated Research Vehicle turbofan engines as a “no development” air ' (TLRV)— with a m a x i m u m speed of 300 supply; the engine by-pass air was ducted to m p h (483 km/h). The TL R V program plan the air cushions. The turbofans also had an called for research in: advantage over electric compressors— the 5 exhaust gas provided thrust that could pro­ conditioning equipment and controls for the pel the vehicle at speeds of more than 100 T L R V were in themselves a significant de­ m p h (160 km/h), making test runs possible velopment program, as described in the sec­ even if development problems held up de­ tion on linear electric motors. The first phase livery of the L1M. of TL R V testing executed without the elec­ tric propulsion system, lasted considerably The TL R V was unveiled in April 1972 and longer than had been anticipated, due to displayed at TR A N S P O ’72 in June before development difficulties with the motor con­ being moved to the Transportation Test trols, power conditioning equipment, and Center (TTC), in Colorado, where G r u m ­ water cooling. Testing began with aero- m a n installed and calibrated instrumenta­ propulsion (exhaust of the turbo fans) on the tion.