THE REVOLUTIONARY DUALMODE TRANSPORTATION SYSTEM
Chapter 11
Getting Onto and Off of the Guideways
VEHICLE IDENTIFICATION
To use the guideways a driver will pull onto an “entry pad” at the edge of a guideway and shut off the engine. An integrated-circuit chip in the car will then identify the vehicle and its owner to the system. Simultaneously the vehicle will be subjected to an automatic safety test of the few components of the car that are vital to guideway-mode operation and safety. All of this will take perhaps thirty seconds.If the computer finds any safety problems; or finds anything wrong in the status of the entering car or driver, the system will notify the driver (or sometimes the police) of the problem and divert the car back onto the streets rather than letting it enter the guideways. Problems such as a stolen-vehicle report, outstanding arrest warrants, lack of current vehicle inspection, no vehicle license, no driver’s license, no insurance, or an overdue guideway bill could be included. Currently we have little real control over illegal use of the streets and highways; but on the guideways we will have automatic means to fully prevent such safety violations and petty crimes, if we choose to use them.
The guideway system will hopefully be paid for by its users, like toll ways and utilities are. But there will be no searching for change at entry pads or exit pads; the REV car identification-chip data, combined with the trip exit-location, will provide the information required for the REV computer to automatically add each additional trip to the bill of the user. The details of our monthly REV bills will be comparable to those of our telephone bills. REV bills will replace gasoline as a budget item.
Data in the car-identification chips will include the length and weight of the vehicles. These parameters will be factors in the formula for determining guideway charges, since more weight will cause a car to use more electricity, and greater length will use more guideway capacity. The fee for putting a big vehicle on the guideway will thus be more than the fee for a minicar. We may decide to charge less for cars with more people in them. This would be the twenty-first-century equivalent of HOV lanes to encourage ride pooling. A photoelectric system would record the number of passengers in each car at the entry pads.
“DRIVER TO SYSTEM”
Before the system will permit a car onto the guideways, the driver must type the code of her desired guideway exit into a keyboard on the dash. (That choice may be changed en route if necessary). Assume the code, LU-WI-4 has been entered. The guideway computer will then show a message on a dashboard screen and also verbally say something like, “You wish to leave the guideways at exit number 4 in Luping, Wisconsin; please press “Y” for yes or enter a corrected exit code.”The choice of exit will permit the computer system to determine the best route (if it is a trip involving more than one guideway of the network) and to automatically navigate the car from one guideway to the next as needed. The “road maps” will be in the navigation computer’s memory.
Like our highway system, the guideway system will require entry ramps from the streets onto the guideways and exit ramps back to the streets from the guideways. But the operation of all cars on the guideway ramps will be automatic.
RETRACTING THE “LANDING GEAR”
Airplanes are dualmode vehicles. As such they require some changes in configuration when they go from the taxi mode to the flight mode, the landing-gear position being the most obvious. Several minor configuration changes will likewise be required in the dualmode cars for REV as they go from one mode to the other.To provide adequate ground clearance in the street mode the levitation and propulsion magnets, as well as the guidance-rail followers in the cars, will be retracted to a safe distance above the road surface. These magnets and units will be automatically lowered while the cars are on entry pads and automatically raised (retracted) when the cars arrive at exit pads. Accidents due to possible failures in this system couldn’t occur, since the cars couldn’t run on the streets with the maglev gear down, and couldn’t run on the guideways with it up.
ENTRY RAMPS
After a car has been processed and accepted for guideway travel, if the traffic is heavy the system will hold the car at the entry pad until the computer has chosen an upcoming space for it between cars on the guideway. Then it will levitate the car, accelerate it to full synchronous speed, and merge it with the traffic on the guideway.The above may sound difficult and dangerous, but those things are exactly the steps we now take when we manually accelerate on a highway entry ramp and merge with the traffic flow. However, the limited mental, visual, and physical-coordination skills of human drivers require leaving large spaces between cars. The synchronized automatic merging system on the guideways will make possible the very close car spacing necessary for high system capacity and low aerodynamic drag.
The LSMs might be operated in an asynchronous induction-motor mode during acceleration, using standard guideway-frequency power. Or they may be left in pure synchronous mode and use tailored AC power of gradually increasing frequency in the entry ramps. Another synchronous method would be to progressively vary the spacing of the LSM coils in the ramps, perhaps in conjunction with AC-frequency ramping.
ACCELERATION AND DECELERATION
In the highway system the entry and exit ramps are long enough to permit the acceleration and deceleration of the cars and trucks within acceptable human acceleration limits and with reasonable thrust and braking requirements. The dualmode guideway system will require similar provisions. If we choose 60mph as the speed for the local guideway system, the ramps will be about the same length as those we use for our present highways. But if we run the intercity and interstate guideways at 200mph or some comparable speed, their ramps will need to be much longer, since the distance required to accelerate or decelerate a body varies as the square of the change in velocity. For instance, to go from zero to 200mph at an acceleration of 0.2g, the ramp length would have to be 6640 feet. This isn’t something new for us however: At airports we call these long acceleration and deceleration ramps “runways.”The requirement for very long ramps to support very high-speed guideways is a major reason why transfer ramps from the proposed 60mph guideways to the 200-mph guideways and return will be built only away from dense urban areas, just as airports are. In fact, in many cases the placement of high-speed guideway ramps parallel with existing airport runways might make sense. It would make very good sense in many more cases if jet travel largely disappears in the post-petroleum era because of prohibitive costs of petroleum and alternative jet fuels. There could also be legal prohibitions limiting flying for global warming reasons. The author predicts that eventually high-speed guideway travel will largely replace domestic flying. This will definitely be the case if we put the high-speed long-distance LSM guideways into evacuated tubes. Then we could “fly” on maglev at the earth’s surface, with very low drag, with no weather problems, and with no high-drag climb-to-altitude and descend time and power requirements.
VELOCITY CONTROL FOR MERGE POSITIONING
The “REVmerging” system will be capable of temporarily altering the velocity of merging vehicles to slightly above or slightly below guideway synchronous velocity, so as to accurately position and “slide” them into selected one-car vacant spots on the receiving guideway. Surely there are high-tech ways of doing that, but this senior citizen suggests the following low-tech method of “fine tuning” the velocity of merging vehicles: Generate the power for the merging ramps with an alternator driven by a guideway-synchronous motor through a differential gear system. The third shaft of the differential would be rotated as required by a servomotor controlled by the merge computer. This merge positioning would be done after the vehicles have been accelerated and locked into sync with the guideway power. Merge-position control will be used not only on the entry ramps, but also at merging guideways and at interchange merges. (Readers who understood that paragraph are entitled to gold stars or honorary degrees in 1940s engineering.)
If, for any reason, something goes wrong with any in-process merge, there will be no crash; the computer will automatically abort the merge by directing the car(s) straight ahead into exit deceleration ramps.
EXIT RAMPS
A car exiting the guideways will be slipped out of line to an exit ramp, decelerated, delevitated and stopped. Then the driver will again take charge, driving on the streets in the normal manner to her final destination. Exit ramps will usually precede accompanying entry ramps; therefore, if the traffic on a guideway is really heavy, an entering car could immediately take a spot being vacated by an exiting car. Multiple entry ramps and multiple exit ramps will be required at high-traffic local areas such as shopping malls, factories, stadiums, and convention centers.The linear synchronous motors in the cars will always be running synchronously while decelerating on the ramps. To explain that apparent oxymoron: There will be no system-supplied power during deceleration. The kinetic energy in the decelerating cars will be regeneratively converted to AC-electric power of decreasing frequency. That frequency will be controlled by the system to produce the desired rate of deceleration. Obviously the spaces between the cars on an exit ramp would decrease as their velocities decrease; therefore each exit ramp could accommodate only a few widely spaced cars at a time. For some technical suggestions on LSM car deceleration, see the APPENDIX, DECELERATION CONTROL.
Next: CHAPTER 12
Guidance and SwitchingBack to: CONTENTS
Last modified: August 02, 2006
