Pallets are not an Acceptable Solution for Dualmode Capability
Kirston Henderson, MegaRail Transportation Systems, Inc.
The recent surge of papers on this debate page regarding use of some sort of pallets as a means to provide a dualmode capability has been interesting. It appears that the pallet idea got new life when the HiLoMag people concluded that it might not be possible to build a dualmode car that could operate both on streets and on a maglev guideway. After reading the exchange, I feel that I have to make some input into the discussion, especially since some writers have incorrectly concluded that pallets are an integral part of MegaRail.
Let there be no mistake that the pallets could provide a pseudo dualmode capability by providing a workable means to carry ordinary automobiles on an automated guideway. Although they can be considered as a temporary, interim means to accomplish the dualmode objective, they are unacceptable for the long term. A true dualmode car should be considered a practical necessity for any successful system. Much has already been said with regard to the problems encountered with pallets and most of the comments are correct.
Some of the objections to pallets voiced have dealt with assumed slowness in pallet loading and unloading and in the size of terminals needed for storing, loading, and unloading pallets. Most of the analysis offered is correct for pallets that must be loaded and then placed on some sort of guideway-based carrier vehicle for transport. However, such a pallet approach is not essential to providing a means to transport conventional automobiles.
Some writers have incorrectly lumped the MegaRail car ferry vehicles used to transport conventional cars into the pallet category. It is important to remind readers that the MegaRail vehicles are true ferry vehicles that enable cars to be driven directly onto and off of while the ferries are momentarily stopped at ramps that pass directly above the loading and unloading rail sidings. This patented system does not involve any pallet loading, handing, or unloading. Furthermore, a unique car wheel alignment system automatically places the car wheels in the correct position as the car is driven onto the ferry. (The driver canšt make a mistake that will prevent the alignment.) Cars entering the system actually never come to a complete stop in forward movement during the loading process. As soon as the front wheels contact the wheel stops at the front of the ferry, backstops rise and the ferry starts forward movement. The momentum of the entering car is actually transferred to the ferry to aid in starting it forward. The rapid loading process described above allows cars to enter the system at about the same rate as cars enter conventional freeways. No entry bottlenecks occur.
MegaRail entry and exit ramps are generally spaced along the rail system in much the same manner as freeway ramps are spaced. This spacing is done under the assumption that the MegaRail lines would operate essentially as automated freeways. Bottlenecks would occur only if only single entry and exit points were used at the ends of a rail segment just as they are on some short turnpikes. In such cases, the answer is the same as for the turnpikes. Multiple, parallel ramps are provided.
A car ferry capability of the type used by MegaRail should be considered as an essential feature for a successful system. Such a feature is an economic necessity to enable a rapid and affordable transition to an automated guideway system. It must be possible for large numbers of customers to use any system as soon as any part of it is placed into operation if such a system is to generate the operating revenues to pay for its construction. Few customers would be willing to purchase a special dualmode vehicle for future or only initial limited use. As a consequence, the time lapse between starting to place systems in operation and the time that significant numbers of customers purchased dualmode cars would be so long that the system would become bankrupt and cease to operate before users could start using the it. Few, including myself, like the idea of having to provide extra equipment to move cars, but such a feature is a necessary evil that we must accept.
Although a car ferry feature is essential to early system success, such an approach should never be considered acceptable as a long-range solution. For the long range, we need a practical electric car that can use both streets and guideway and recharge its internal batteries during guideway use. Such a car is probably the only practical means of providing practical and affordable electric cars. I don't believe that many people will dispute the idea that we must find means to operate cars without conventional fossil fuels. The guideway system must be designed to accommodate such cars. Such cars will have to become the primary means of transportation for most people. Public transit will not satisfy the needs of most users.
Furthermore, the guideway system must enable a dualmode electric car to use the same suspension and drive train for both street and guideway use as means to limit car complexity, cost and weight within acceptable limits. With the proper approach, it probably possible to provide such a vehicle at a cost that is slightly below that of conventional cars.
Unfortunately for those strong advocates of maglev and steel wheels, it would be almost impossible to produce a practical and affordable dualmode car that would use either type of suspension. Such is a nice dream, but is likely to be an economic and physical impossibility. We must bear in mind, that simple economics cannot be ignored in system design. The road to advanced transportation is already littered with failed systems that have either disregarded or misjudged the controlling economic issues. Any successful system must be affordable to the user and must offer the desired service at a reasonable price. Simply using advanced, presumed high-tech approaches does not get us there.
Last modified: May 27, 2001