Searching for the Optimum Dual-mode, Continued


Francis Reynolds

Responding to K. Goltermann, and J. Richard Guadagno

July 22, 2000

The goals of the HiLoMag team are a little different than those of the dual-mode companies. This informal team will never build HiLoMag or any other system, nor will we accept any contracts. We are mostly retired engineers with no financial goals in transportation.

All HiLoMag ideas are in the public domain. We are trying to give away any good thoughts we have. If something in the suggested HiLoMag system is the same in another system, we may or may not have thought of it first. At any rate we are not stealing that feature, we are endorsing it.

We are willing to change horses when it seems advisable. But when we do we painfully admit that we weren't right in the first place. And what is "right" in this game? The factors involved in most of our dual-mode choices are so numerous and complex that there are no unequivocally right answers. The best answers are the ones that take into account all of the factors and apply the proper weighting to each factor. And what is "proper" is usually a matter of opinion. Also, the weighting we give a factor is apt to change as we learn more and as conditions change.

Mr. Goltermann tells us that HiLoMag was on the right track earlier (when the guideways supported the cars from below). But now that we are proposing to suspend the cars from an overhead guideway (like InTranSys, Higherway, SkyTran, Monomobile, Flyway, and a number of single-mode systems), Goltermann thinks the HiLoMag system "is a loser." My wife thought changing to a suspended system was a bad move too, at first, but she now sees the whole picture. It is interesting that some people will say they wouldn't ride in cars suspended eight feet off the ground, but they ride in airplanes 35,000 feet off the ground. I would prefer to ride eight feet up where my vehicle can't hit pedestrians, animals, and other vehicles; yet the fall would be short, and from a guideway I know that I would not land in the water or in a forest.

The many advantages of suspended car systems were discussed in my previous "Searching for the Optimum Dual-mode System," but Goltermann doesn't take issue with any of those claimed advantages. Instead he seems to ignore them and gives no reasons why a suspended-car system is not to his liking. He is very concerned with cost, so he should be pleased that a suspended system can probably be built for less than a supported system, as explained in the earlier article.

Goltermann says, "our preferred solution will have to be decided on by politicians with tight budgets." Heaven help us! We believe that our national dual-mode system will be built by private enterprise the same as our railroad system was built by private money. The government will have to be involved to the extent of blessing this transportation revolution, and participating in the establishment of dual-mode system standards. But we see no more than a few small initial USDOT study contracts and a continuing government presence comparable to that on the railroads prior to the Amtrak takeover.

Get out of the subsidized-transit-system mindset. Transit systems and railroads were once profitable businesses because they offered better transportation than walking, bicycles, and horses. When the automobile became affordable to the masses we chose to subsidize the transit systems and the railroads rather than let them die. Dual-mode will be a profitable and even a taxpaying system, because it will be used by almost everyone, the way our highways are used and the way transit systems and railroads once were.

Sorry, Mr. Goltermann, I cannot agree that our system should "be a cheap and minimalist solution." Quite the contrary: Since we have huge worldwide transportation and related environmental problems of many kinds, no cheap and minimalist solution will do the job. We have been applying cheap and minimalist patches for much too long already—with minimalist results.

We want about the best and safest high-tech system money can buy—at least I don't want to bet my life on anything less. We want a revolutionary system that will carry most of the traffic of the nation and much of the rest of the world for the next hundred years; replacing most of the highway travel, most of the railroad travel, and much of our domestic airline travel. These old systems are obsolete under current and future conditions, and it makes sense to solve as many of the resulting problems as we possibly can in one grand revolutionary system. Dual-mode is the only type of system that can do the whole job—but it has to be configured and designed wisely. Sure, planned revolutions are hard to sell, and we may not succeed (See Hopkins), but we must try.

Goltermann went on to question the need for a 200-mph dual-mode system speed. He wrote, "High speed is not a quality that weighs in heavily when determining the requirements of a future transport system." Oh, but it is, if we are doing the whole job at once, as we should. Reread the latter part of Guadagno's last contribution. Not only are our streets and highways jammed, our airports are jammed, and there is tremendous opposition to the addition of new airports, and to the addition of more runways to existing airports. Almost everyone flies sometimes, but almost no one wants the planes over their backyard.

HiLoMag at 200 mph between cities will make it faster to take ones own car than to fly, for trips of up to approximately a thousand miles. This takes into account all of the many time-consuming aspects of flying: The reservations, getting to the airport, parking, baggage-checking, security checks, late flights, cancelled flights, weather delays, waiting for a takeoff runway, sometimes "stacked up" waiting for a landing runway, missed connections, baggage retrieval, renting a car or waiting for a shuttle bus, etc. (And we will have our own car to use at our destination if we use the guideways instead.)

Similarly, Guadagno has independently estimated that at 150 mph their InTranSys dual-mode system would get people from door-to-door faster than airline travel "for distances up to at least 750 miles." A major percentage of our domestic airline trips are less than 750 to a thousand miles. Oh—and taking the guideways will be a lot cheaper than flying.

The airlines are a big drain on the world's rapidly dwindling petroleum resources, and great contributors to global warming. There are several other (lower performance) ways to power cars when the oil is gone, but there is currently no other way to power airplanes. Dr. Guadagno, after much work in the field, has predicted that our petroleum, worldwide, will be essentially gone in twenty years. If he is anywhere near right the airlines are living on borrowed time. Dual-mode will delay that day, if we have sense enough to build it as soon as possible. Mr. Goltermann thinks we should retain internal combustion engines in our dual mode cars. He is obviously planning for a very short-lived system, if it could be built at all before the oil is gone.

But Goltermann does make many good points. I agree for instance, that "Any proposal must build on our existing transport industry's expertise and capabilities." That does not mean however that our dual-mode cars need to have internal combustion engines, need to look like present automobiles, or need to operate like our present automobiles. And we will all agree that cost is important, but I come back to the "Penny-wise but pound-foolish" warning. We must spend enough money to do the job right.

In the airplane design business there is a dictum (grammatically messed up for effect and humor): "Simplicate and add lightness." When gasoline was cheap and looked like it would last forever, weight in automobiles was thought to be unimportant. Weight has always been important in airplanes. Now it is time for the automobile industry to adopt the aluminum-alloy structures and the composites technologies so well developed by the airplane companies. Admittedly, there is much work to be done to make these light structures as cheap in mass production as automatically spot-welded steel bodies.

"Keep it simple, Stupid" is another good dictum. The best solutions are apt to be simple solutions. Unfortunately, many things that seem simple at first glance turn out to be far from simple when we really understand their details.

Goltermann would "add a couple of simple magnets to the bottom of the car for LSM propulsion." Would that it were that simple. On the other hand he sees magnetic levitation as something complex, expensive, and untested. There have been three or four different types of full-scale maglev systems developed and tested on trains over a period of several decades. The speed record is 350 mph, and maglev trains have carried two and two thirds million paying passengers with no accidents. Actually the magnetic levitation and the linear-propulsion technologies are remarkably similar and closely related. In some configurations one set of hardware can be designed to do both jobs. In other words, some permanent magnets and some electromagnets can replace the wheels, steering, transmission, and the engine of conventional vehicles. Maglev technology is wonderful, but don't use it on trains, because the very concept of coupled trains is obsolete.


Dr. Richard Guadagno has become more of a partner than an opponent in these debates, since the HiLoMag system has become more similar to his InTranSys. We agree on many more things than we disagree on. And we agree on a new point or two that he will just now hear about. This is not to say that I won't still try to give him a bad time on a few of the current choices on InTranSys.

The recent HiLoMag decision to use overhead guideways with the cars suspended below came out of the many-faceted analysis of integral vs. separate pallets. A few days after I had submitted my July 5th debate contribution to Jerry Schneider the HiLoMag Team held a meeting and made some more changes. We hope some of the following ideas (not all of them original) will be useful to other dual-mode groups.

During our meeting electrical engineer Dan Bray argued that in spite of how nice it would be, a pallet integral with the car would have to be too big and heavy to neatly fit inside a fairing on the roof. And the group felt that the increase in the cost of the cars would be serious if they were made true dual mode. Increases in car cost were thought to be more serious than increases in guideway use fees would be if pallets had to be provided and the system had to be more complex in order to route pallets to where they were needed.

The problems of shuttling empty pallets in one direction during morning rush hour and in the other direction in the evening, and the problems of automatically storing them were discussed. Dan then suggested that a single-type of small standard basic pallet be provided by the guideway system. One of these would be attached to a front socket, and one to a back socket built into the roofs of the cars. These sockets, perhaps slightly reminiscent of trailer hitches, would be recessed on the roofs, and would add little to the cost of the vehicles.

It may also be practical to retrofit the sockets and the required supporting structure to at least some vehicles of current design. But since a dual-mode system will take a couple decades to design and build, existing vehicles will be worn out by then, therefore retrofit doesn't appear to be a very useful option.

To put small and average-sized vehicles on the guideways one standard pallet would be used at each end, but on heavier longer vehicles, such as buses and freight containers, two, three, or more standard pallets would attach to each end of the vehicle. These multi-pallet modules on long vehicles could be designed to swivel with respect to the car, so as to remain tangent to the guideway in turns, like the four-wheel "trucks" swivel on railroad cars.

The arms on the standard pallets that connect them to the vehicles would retract by swinging back when the pallets are not in use, so that empty pallets that needed to be routed elsewhere would be entirely within the overhead guideway channel for minimum drag and better appearance. For routing en masse to a pallet-deficient area the standard pallets could be bunched together into a train of pallets, and sent by one set of commands. The retracted arms could serve as automatic couplers between pallets if coupling them and using the LSM of only one of them would reduce the energy required for pallet routing.

Using small standard pallets, two or more per car, will greatly reduce the magnitude of the pallet distribution and pallet storage problems. Routing short empty pallets will use less energy and less guideway capacity than routing empty vehicle-length pallets would. So, Dick, we now propose pallets that stay with the guideways, as yours would on InTranSys, but our pallets are considerably different from yours. If any part of these pallet ideas should appeal to you, help yourself. We would be honored.

You gave us some history on the evolution of your pallet system, and noted that your first design included connectors located on the roof of each vehicle. You expressed concern over the roof structure required to support the load. We feel that will be no problem.

The roof-support structures on existing automobiles were made rugged enough to resist crushing on rollover accidents. Such accidents induce compression, bending, and impact loads in the roof posts. Since they were designed for such big loads, existing roof posts would be more than adequate to support the cars in the tension mode during suspension from the guideways. One forward and one aft roof beam will have to be adequately strong in bending to take half the weight of the car at the center of each beam. But we are talking only several added pounds and a few dollars; many pounds and many dollars less than the platform type of pallet system now proposed for InTranSys.

Tension loads are met easily, and the inertia loads produced by the smooth guideways will be very small compared to the various inertia loads produced by human drivers on rough roads and potholes. The previous HiLoMag configuration with integral heavy pallets carried on the roof would probably have required stronger roofs just to support the pallets in street mode than would be required to support the entire car in tension on the guideways.

Dick, you correctly observed that certain types of roof suspension would exclude useful and popular rooftop racks. But with just two thin supporting arms attached near the ends of the roof, many roof racks and loads will still be possible. The height of roof loads will be limited by the length of the supporting arms between the roof and the overhead pallets, just as the height of roof loads on InTranSys would be limited by the length of the columns. At a hundred and fifty or two hundred-mph most loads would be excluded from the vehicle roofs anyway, but those that could withstand the drag and "whipping" forces would have to allow room for the pallet-supporting arm attachment at each end.

When we compare the two short arms on HiLoMag pallets to the InTranSys sturdy and therefore heavy platform, wheel clamps, four vertical columns higher than the height of the vehicle, and the upper array of horizontal connecting bars, we are not tempted to adopt your system.

The column heights and the spacing of your four columns would have to be tailored to the size of the vehicle, or be grossly oversize for small cars. Our supporting arms don't care about the height, width, or length of the vehicle hanging from them. And whether the parts are streamlined or not the aerodynamic drag of your platform system would be many times the drag of our two small arms. The interference drag between the top of your platform and the bottom of the car would be particularly high.

Our guideways will of course be banked to the angle consistent with the radius and the synchronous velocity, but we will also hinge the support arms at the pallets so they can articulate laterally and relieve unbalanced forces on the pallets due to side winds and online emergency decelerations in turns.

You wrote, "figures show that the average car is moving only about 3% of the total time." Then you said carriers and platforms could be used about 60% of the time, and you divided 3 by 60 and came to the conclusion that you would need 1/20th as many carriers as cars. The arithmetic is correct, but the conclusion is invalid. The percentage of the total time the average car is moving has nothing to do with the number of pallets needed. During rush hours a very high percentage of all the cars will be using the guideways, and there would have to be a platform available for each of them.

Further, there would be still more platforms en route to the residential areas in the morning and to the business and industrial areas in the evening. Or with your solution, a lot of platforms would be waiting for customers in hopefully the right places (and more space would be required at the stations to store a rush-period's worth of platforms). Our guess on the fraction of pallets required is closer to one per car than it is to 1/20th. And in HiLoMag the system would supply only the pallets (carriers), while in InTranSys you would have to supply both carriers and platforms. I don't like it, Dick.

On the first page of your contribution you wrote "Maglev requires the constant application of an upward force (and therefore the constant expenditure of a great deal of energy) just to keep the vehicles suspended above the roadway." I am sure you are referring to the I2R losses (which are quite small actually), but for readers without a technical background we need to point out that just holding something up in the air doesn't require any energy or work. Work is force times distance and here the height is constant so there will be no "distance" normal to the force of gravity. Permanent magnets can suspend a load indefinitely without the expenditure of any energy, just as the studs of a house hold the roof up indefinitely without using energy. I have a novelty ballpoint pen that floats above a base by magnetism. It has no batteries, and it floats just as high now as it did years ago.

With regard to dual-mode system implementation, HiLoMag Team member Paul Weston suggested that initially sixty-mph bidirectional guideways could be built to ease the daily traffic jams on saturated freeways. Guideway grids covering the cities could come a little later, after the public had learned to like the earlier linear segments and could foresee the merits of a grid throughout their city. And the 200-mph guideways connecting cities across the nation would doubtless be the last to be built. But it all has to be coordinated and standardized before anything is designed and built. Ten different systems in ten different cities could not be interconnected efficiently if at all, and they would all cost more than they would if they were standardized because their diversity and limited production would preclude major mass production savings.

A one-way-only guideway grid system can be built (like a grid of one way streets) with little loss in utility but a great reduction in guideway-system costs, and great reduction in the land area required for the system. This basic idea was borrowed from David Triantos as described in the Web site of Tad Winiecki's "Higherway" system. The HiLoMag concept of "turnaround loops," for safety in the event of local power outages and other emergencies, will work very well in a one-way grid system. There it will work even better than on bi-directional straight-aways, where the safety loops will need to be added. On a one-way grid system the basic quadrilaterals of the grid itself will provide the turnaround loops so that a failed area will be isolated safely and the rest of the system will continue to operate normally. This is easy to see on a diagram, but difficult to get across with words.

Again I express my delight with these debates. Two heads are better than one, but ten heads are better than two. The interaction forces us to be honest with ourselves and to reexamine our previous convictions. We are learning from each other, and making real progress.


Last modified: July 22, 2000