Abstract:
This is an elevated pile supported pre-stressed concrete beam electric high-speed remote-controlled modular train system, including compact high-rise terminals installed within the interstate highway rights-of-ways, a train module astride elevated support beams at standard gage rail widths to fully integrate train modules into existing rail, and since it&#39;s within existing interstate highways, fully integrates the new train system with other transportation infrastructures.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/646,298, Jan. 24, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The reason trains haven&#39;t re-invented themselves is mainly based on: the kind of innovation used, economics, and incompatibility with existing infrastructure. Maglev is very innovative but cost&#39;s over $60 million a mile or more to install in a rural setting; much higher costs can occur within city limits. After China built a 20-mile section at $1.2 billion, it promptly announced maglev wouldn&#39;t be the new future for trains in China due to cost and because it doesn&#39;t integrate into existing railroading infrastructure. For similar reasons, Germany, having spent billions of dollars developing maglev, promptly announced it would not be applying maglev on a national basis either for the same reasons. Innovation by itself is not enough to re-invent train technology, it has to be innovative, economic and work with existing track and road systems.  
         [0003]     Today, elevated train systems generally include monorail rubber wheeled or maglev or standard gage trains. Generally, monorail trains aren&#39;t steel rail based, but have rubber wheels that ride atop steel or concrete beams and that have horizontal orientated wheels that straddle the beam to prevent the train from tipping over. These rubber tire trains aren&#39;t designed to go fast or be maximally fuel-efficient and are generally only used for in-city people transport. These rubber wheeled train technologies teach a side-to-side shifting of long beams to switch to a new line, which could be cumbersome and dangerous at high speeds. These trains also suffer from the inefficiency of rubber tires, and low speed capability. They are elevated to prevent collision with other vehicles and animals (environmental acceptance).  
         [0004]     Maglev uses an elevated beam but suffers from very high cost of construction due in part to the precision aligned magnetic rail and high cost of train modules and controls; $60 million a mile was spent for the China project with recent news stories saying Germany is abandoning maglev as a result of the high cost and China also announced in January 2004 it&#39;s abandoning maglev as well for it&#39;s larger new train system similarly due to cost and because maglev can&#39;t integrate with their existing rail system. Even some rubber tire city monorail systems in the US are approaching $70 million a mile. The beams are elevated to prevent collisions with cars and animals so as to achieve an acceptable design environmentally at high speeds. The cost of meeting all the above conditions of use with maglev are very high accounting for very limited application of this technology. Shifting maglev carrier modules to conventional rail is not practical limiting practice between two destination points where shifting to other rail systems is not required. This is unjustified for a new national train system.  
       SUMMARY OF THE INVENTION  
       [0005]     This invention relates to a lightweight high-speed train system and utilizes a beam support to eliminate animal and general detrimental environmental effects i.e. to avoid hitting mammals and colliding with other vehicles and the like. It teaches how to achieve a high-speed and safe elevated train by straddling a deep pre-stressed concrete or steel beam with conventional steel train wheels and standard gage width for the rails. Thus it can use standard switching systems, use improved standard switching, or a new ramp switching technology proposed herein which has certain advantages, namely assisting with decelerating the train module entering the station and accelerating it when leaving. It&#39;s designed for high-speed long distance travel between cities with people or light freight on the order of 200+ MPH (miles per hour) with a minimum of energy. And since such beams should be thicker near the base to provide side to side stiffness long spans, about 100-150 feet in length between post supports, the side of the beams conveniently provide standard gage rail spacing, another main advantage of this invention over others proposed.  
         [0006]     The train system of this invention can be located anywhere within the interstate highway system and in the most developed city areas to provide jobs and redevelop these areas, or in the most rural region of America probably using conventional switching technology to bring train modules down to ground level to be serviced by existing highways and track systems everywhere.  
         [0007]     Just as the first trains systems revolutionized America and dominated investment at the time, this new train system invention can do the same due to it&#39;s high-speed potential, electronic drives, and high stream-lined high-speed efficiencies and comprehensive connection possibilities. With this invention, a module can travel from existing rail lines to the new switching station and be launched onto the high speed line with no interface problems whatsoever. Other new national system train proposals don&#39;t accommodate existing train technology or road systems like this invention.  
         [0008]     This system re-invents the train by integrating new technology into old. It removes the environmental problems that high-speed trains create by economically elevating the entire track. It solves the overall economic problem by integrating the system within the interstate highways rights-of ways and combining a government financing rail-line construction with total private financing of train modules with municipal and state financing of train stations. It is an economic model designed after our air traffic system except that train modules are pilot-less, i.e. totally remote controlled from a central control room. It also creates a new level of high-speed train safety by making the train ride astride the ribbon of elevated beams making derailing virtually impossible; an important consideration at such high speeds.  
         [0009]     Just as the public owns the airways, they own the track-ways in this new system, but get paid back from building it with a tax per person or per ton-mile used, or some similar payback scheme. And just as cities own the plane terminals, so they own the train terminals described herein. And just as private industry innovates in planes, so they own and innovate with train module technologies to haul every conceivable cargo with high aerodynamic efficiency, and such aerodynamic module efficiency should be mandated by Congress in order for private companies to be able to use the new rail system. Congress should also mandate the kind of control technologies used since control technology universality is required in such an automatic system.  
         [0010]     In short, this train invention will pay it&#39;s own way, conserve huge amounts of oil, move goods and people fast with much less energy than planes and trucks and busses, yet be fully integrated into every other existing transportation infrastructure. For example, the cost to move a person from New York (NY) to Los Angeles (LA) at 200 MPH in electricity is about $7 each. The projected cost in electricity to freight-forward a container the same distance at 200 MPH is $469. Using diesel to do the same trip would use 400 gallons of oil at $2 per gallon or cost $800, yet the truck travels at a fraction of the average speed. The truck requires a driver, the train doesn&#39;t, the truck takes at least 4 days to get there, the train 14 hours, and the train module never gets tired or interferes with normal road traffic and can run rain or shine or during the greatest snow fall with special high-friction traction units, melting systems, or foul weather track-traction-sprays.  
         [0011]     All train modules whether freight or passenger are remotely controlled from a central control room and are tracked using transponders, radar, and GPS, or multiple location technologies for reliability in train location for the control purposes.  
         [0012]     The load width and weight of train module will vary depending if it&#39;s freight-forwarding containers or for passenger service or utilized for specialty freight service. The unit shown is a width for passenger service and is 11 feet 10 inched wide to allow for comfortable side by side seating for 4-5 rows of seats plus a narrow aisle like in airplane fuselages. Due to the high speeds, experts say tunnels should be avoided. And opposite direction lines should be on opposite sides of the highway except for bridges wherein rail lines may come together for practical treasons. This would likely limit the speeds, however, should trains pass by each other on a common bridge structure (the control system knows when this will occur and can adjust module speeds accordingly).  
         [0013]     The conventional looking train wheels straddling the beam would likely all be driven through gear units opposite the wheel axle as shown. High rpm (about 12,000 rpm) lightweight vertical motors driving the right-angle gear reducing units would likely be a normal, other arrangements are possible. Drive motor and parasitic train power is shown picked up from conducting rods mounted atop the beam under the train fuselage using spring loaded brushes connected to the underside of the yoke supporting the wheel frames of train fuselage, or power can be taken from atop modules from suspended power cables which is also normal for high speed trains.  
         [0014]     To save train weight in the invention, there are air ride module suspensions with active shock units that can operate much like speaker coils, or shocks can be active pneumatic or hydraulic process technologies, all to counteract side to side and end to end buffeting forces that would diminish the ride quality and speed capability of the train module. The speed of response of electronic shock absorbing units has been amply demonstrated for active automobile suspension systems and now is available in the automotive market. A stabilizer bar between the underside of the load fuselage and the wheel support yoke is also provided. Gyro&#39;s can also be used on passenger modules to provide even more stability on side-to-side shifting.  
         [0015]     As shown, the train has about 147 square feet of projected area. Thus, with a possible streamlined drag coefficient of 0.090 or less, the maximum power required to overcome air friction to reach 200 MPH is about 1195 pounds force requiring only 637 steady state horsepower. Rolling friction power would be about 7.5% of that (90 pounds for an expected 90000 pound 80 person passenger module with rolling friction coefficient of 0.001) for a total power requirement of about 684 horsepower or 510 KW. To allow for hill climbing and given that IGBT electronic motor drive modules likely to be used and that are built in about 200 kW units, 1200 KW (6 powered wheels) would likely be installed per module enabling a 90,000 pound loaded module to climb a 3% grade at about 160 MPH. Assuming a power cost of 8 cents per kilowatt-hour, energy cost per passenger from New York (NY) to Los Angeles (LA) at 200 MPH average speed for the 2800 miles would be about $674/80 people, or about $7 per passenger for the whole trip excluding minor parasitic power uses. Being a fully electric system, braking energy can be fed back into the power gird used for the new railroad.  
         [0016]     Cost of construction for mile supported beam systems can be reasonable since beams cost about $150 per foot and pile should cost roughly half that to install. Except for terminals and rolling stock and control centers, such a train rail system if 100% elevated would cost about $1.25 million per mile plus engineering and profit or about $6 billion ($2.2 million per mile) to go from NY to LA. Not included in this cost is switching and elevated terminal costs which would be provided by local entities, and specific rolling stock or train modules which would be provided by the business entities needing them and that would be operating out of the various terminals, much like airlines, which in some cases (freight) would be supplied by the business entities and not the municipalities or cities involved. All train modules would have to meet the same specifications of the railway and be tested to insure specifications are met. Within the terminal, rails are at grade and standard switching technologies are easily utilized including taking train module off the main lines as well as a lowered and raised ramp system in rural areas.  
         [0017]     At 5-minute train separations, 288 trips a day per line on average are possible east to west one way. It&#39;s estimated a train module would need to be about 80 feet long to accommodate 80 passengers seated 4 abreast. If a line in one direction between NY and LA costs the federal government $6 billion, and if the government rented a line at 2 cents per passenger mile and assuming 50 passengers per car, that federal government would take in revenues of about $300 million a year for that line. Thus at $6 billion per line between NY and LA (no other infrastructure cost to the federal government), it would take 20 years for the government to get its money back on building the line (at no interest). This is not a bad investment considering all other Federal train investments are highly subsidized and have no payback whatsoever. For container or truck shipments, they would likely pay the government ½ passenger rates or 50 cents per mile. Thus the average payback period could be as low as 30 years with ½ freight and ½ passengers.  
         [0018]     This invention is called “Interstate Highway Train System” because the whole system is preferably, but not necessarily, enclosed within the interstate highway rights-of-way including elevated terminals (hotels, freight systems, passenger terminals, existing train connections, helicopter pads etc., all located above the existing interstate highways rights of way for quick access by cars and busses, tractor trailers, existing train lines). Note that heavy existing train units would not be allowed within such a terminal, only the high speed modules connecting from existing track to the high speed tracks would be allowed into the elevated high speed train terminal. There are no train drivers or operators, just large computer control rooms like for airplanes with big TV screens, radar, GPS and transponder locator systems; or enough redundancy to provide reliability to control train module speeds, and to switch modules off main track lines into terminals and back onto main tracks lines.  
         [0019]     Trains that must travel on snow covered tracks at high speeds need track systems with a snow melting method on the tracks plus special traction sprays built into the train module to provide adequate friction traveling up grades as steel on steel wheels will likely slip under these conditions at the high speed horsepower or toque needed. Or, while not shown, special high friction drive wheel modules attached during winter months could be lowered onto the tracks for extra drive force. This high friction modular wheel and traction spray systems would be removable for non-snow season so as not to waste energy from the extra weight involved.  
         [0020]     Also, different trains would likely have different speed goals at different times of day. For example, to save energy, extremely bulky train shapes, while streamlined, might be allocated to a lower speed time slot to save energy, since it&#39;s frontal area coupled with speed that causes the consumption of energy more than weight in such trains.  
         [0021]     As noted, this invention has steel train wheels straddling the beam by use of devises or wheel frame supports providing much more flexibility, safety and considerable cost reduction over maglev, and should cost less than rubber wheeled train technologies. The rail is supported on shoulders protruding out the side of the beam, needed to give long beams side-to-side rigidity in any event. And the rail installation allows rainwater to freely drain through slots under the rail and provides for a snow and ice melting system. The wheels are spaced at standard gage and use conventional wheel shape including inside rail wheel flanges to enable standard switching technology to be used. Considering the considerable train infrastructure that exists, it would be impractical to do otherwise. This gage feature of the system is not to allow heavy and awkward existing trains onto the new interstate system, but rather to allow the new lightweight modules to travel on existing rail systems and back onto the new interstate train system at will, enabling conventional switching at terminals for train modules from existing track systems, i.e. to deliver cargo modules and passengers to the interstate based terminals, perhaps using a battery powered hauling unit form the conventional track system until the remote controlled electric powered modules are switched into the new rail system.  
         [0022]     Also, this invention teaches the use of air ride and active shock absorbers. Such active shocks can be either electric speaker-coil type shocks or possibly even pneumatic or hydraulic, providing the adjustment that can be made fast enough to absorb forces from wind buffeting and the like. The air ride allows the train body to stay at the same elevation regardless of the load, and to tilt the loaded space to achieve a levelized ride sensation by tipping the train when going around curves. In addition, the air suspension independent wheel support system eliminates the need for heavy tandem bogie support assemblies as used in existing steel-wheeled train technology saving weight due to greater wheel spacing thus reducing the number of support wheels required and reducing the beam stresses as well. Gyro&#39;s also can be used to advantage on the very highest speed transport modules to stabilize the train in the worst cross wind conditions, and when coupled with active shock absorbers makes for a jet plane-like ride capability. Such gyros are used on ships and were used on a prototype steel-wheeled monorail train by Lewis Brennan 100 years ago, but also can be used advantageously on this high-speed passenger train module as well (gyro&#39;s not shown).  
         [0023]     Some unique aspects of this train invention system that uses steel wheels and standard gage are: 
        1. Vertical wheel frames or devises support individual wheels and their respective drive and suspension units making it possible to straddle an elevated beam with rails mounted down the beam&#39;s sides, and air ride combined with active shock absorber and gyro stabilization eliminating the need for heavy boggy wheel assemblies.     2. An environmentally friendly elevated beam-straddling train module with standard gage rail system providing high-speed capability with efficiency, stability, reliability and, due to the straddling feature, maximum possible safety against derailing at high speeds.     3. Minimized side to side and end to end train motion from wind and track irregularities by utilizing active shock absorber system and gyros, while air suspension ride enables tipping the train to reduce curve traveling effects on the occupants of modules.     4. Elevated platform ramp-up switching to recover energy and to slow the train entering the elevated terminal yet accommodates conventional switching technologies as well depending upon which is more appropriate.     5. Track deicing system and to create extra drive force or friction, special track sprays or alternative high friction drive wheel modules could be lowered into the tracks for slippery winter conditions.     6. Remote controlled train modules; no drivers are needed nor are they desirable for such a high-speed train system either for maximized safety or economics.        
 
         [0030]     The present invention and its advantages over the prior art will be more readily understood upon reading the following detailed description and the appended claims with reference to the accompanying drawings. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0031]     The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:  
         [0032]      FIG. 1  is a vertical schematic section of one embodiment of a train fuselage, showing wheel and active suspension yoke position and drive motor arrangements.  
         [0033]      FIG. 2  is a vertical schematic section of another embodiment of a train fuselage showing wheel and active suspension yoke position and drive motor arrangements.  
         [0034]      FIG. 3  is a vertical schematic section depicting three trains, one about to enter a lowered ramp decelerating the train to a raised train terminal platform and a train accelerating down platform onto the elevated track systems. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]      FIG. 1  shows a train and rail system in accordance with one embodiment of the present invention. The system includes an elevated beam railway and a straddling beam rail vehicle. While the rail vehicle of  FIG. 1  is a locomotive, it should be noted that the present invention is applicable to any sort of rail vehicle including rail cars and the like.  
         [0036]     Generally concrete posts or piles  1  supporting rail beam  2  would be spaced and be connected to piles  1  every 120 feet or so depending on the width and thickness of pre-stressed concrete or steel beam  2 . All things considered, pile supported beams  2  are probably more economic than at-grade fenced rails foundations, even in deserts, especially considering the economic disadvantages of long fences and due to the potential economic loss that restrictions to local cross traffic can cause. Beam  2  could be steel but generally pre-stressed concrete would be the most cost effective beam support if held under  120  feet between pile supports, however, longer and longer pre-stressed beams are being manufactured. It&#39;s a compromise between beam deflection that can be tolerated by the rails and the economics of driving and grouting piles. Generally it would seem that shorter pre-stressed beams would be desirable to maximize the lifecycle of the elevated beam system, which should have a minimum 100-year design lifecycle.  
         [0037]     Methods to connect beams to concrete posts are well known and are not part of the teachings of this invention. The beam shoulders  3  and  4  support a track or rails  5  with respective rail beam retainer bolt  5 ′, and rail  6  with respective rail retaining bolt  6 ′. Shoulders  3  and  4  of beam  2  also provide the extra resistance to buckling needed by pile supported pre-stressed long concrete beams, and enable standard rail gage to be used as shown.  
         [0038]     Referring to yoke  14  mounted components and wheel parts, with the exception of the yoke and power lines and power take-off brushes to be described later, yoke  14  is common to both wheel units on the sides of beam  2 . On the left, rail  5  supports flanged wheel  7  and on the right, rail  6  supports wheel  8  (assuming the train of  FIG. 1  is traveling into the paper, which will be the assumption hereafter). Rails  5  and  6  would be mounted and attached to the concrete by well known methods and joined end to end similarly to provide a noise-free ride, and rails and wheels would be hardened and polished to provide minimum rail rolling friction and maximum safety as regards to strength. Wheel  7  is supported by axle  9  which rides in roller bearings  10  and  11  which are attached to inner and outer wheel frames  12  and  13  respectively which are connected to common yoke  14 . Similarly, wheel  8  is supported by axle  15  which rides in roller bearings  16  and  17  which are attached to wheel frames  18  and  19  respectively which in turn are attached to common yoke  14 . As needed, multiple (one each shown in  FIG. 1 ) side or horizontal wheel assemblies  13 ′ and  18 ′ attached to inner wheel frames  13   18 , respectively, will enable the train to stay on the tracks if an object on rail  7  and  6  should cause the train to jump up whereby the stabilizing wheels  13 ′ or  18 ′ together or separately will cause  13 ′ and  18 ′ rub and spin on the side walls of beam  2  in the areas of  13 ′ and  18 ′ to hold the train on the track, an added safety feature to this elevated train invention.  
         [0039]     Alternatively, each wheel unit can be provided with two sets of horizontal wheels assemblies, one above the other, for added safety. As shown in  FIG. 2 , lower horizontal wheel assemblies  13 ′ and  18 ′ are attached to inner wheel frames  13   18 , respectively, and upper horizontal wheel assemblies  13 ″ and  18 ″ are attached to inner wheel frames  13   18 , respectively, above the lower horizontal wheel assemblies  13 ′ and  18 ′.  
         [0040]     In the illustrated embodiment of a locomotive, axle  9  is connected to a telescoping drive shaft with universal joints  20  which in turn is attached left side right-angled gear box  21  which is attached to what is probably AC motor  22  which is attached to underside of the train fuselage base  24  respectively. Cowling  25  covers these components left of center of the train and is also attached to  24  and provides for storage compartments (not shown) under  24  between drives. Right wheel axle  15  is attached to a telescoping drive shaft with universal joints  26  which is attached to right side right-angled gearbox  27  which is attached to vertical AC motor  28  attached to base  24  respectively. The right-side drive components are covered by cowling  29  also attached to base  24  which like cowling  25  provides for storage under  24  between drives. Vertical AC motors  22  and  28  would typically be speed controlled using IGBT controllers, not shown. Companies skilled in the art of such drives would provide the proper arrangement, but generally higher speed motors in the 12,000 rpm category and higher result in lighter drives. And as noted above, the spaces under base  24  between wheels and or drives and between the sides of the beam and inner cowlings are spaces that can be designed to accept passenger luggage and other commercial cargo that fit such spaces. Also note that the train stabilizing gyro&#39;s referred to earlier are not shown since such technology is well understood and was practiced 100 years ago by inventor Lewis Brennan in the UK and would also be located between drives. Spray-on rail traction material units for each track would be located at the very front of the train module (not shown) to enable every drive wheel to achieve higher traction during poor weather conditions, i.e. when such spray is needed.  
         [0041]     Referring to fuselage yoke  14  for mounting air ride components, air ride unit  30  and electronically controlled stabilizing shock absorber  30 ′ left are mounted between the top of yoke  14  and under side of fuselage base  24 , and similarly on the right side air ride unit  31  and electronically controlled stabilizing shock absorber  31 ′ are also mounted between the top of yoke  14  and underside of base  24 . These active shock absorbers can be electric operating much like a speaker coil, or be pneumatic or hydraulic, with electric being the fastest responding and which have been developed for automotive applications. The related sensors and actuator details to instantaneously operate  30 ′ and  31 ′ respectively are not shown, but would be well known to those skilled in active suspension arts including use of needed sensors. The air ride supports  30  and  31  eliminate the need for bogies, so wheels can be located anywhere along the axis of the support base  24  saving weight by eliminating the tandem bogie support assembly allowing longer spacing between sets of yoke mounted wheel assemblies thus reducing stress on the train fuselage and support beam  2 . Side to side suspension rigidity is supplied by pivoting or hinged stabilizing or anti-sway bar  32  mounted between the top of the yoke  14  and under fuselage position  24  as shown. Power through conducting rods  32 ,  33 , and  34  (or more as required) are mounted atop the concrete beam  2  would be picked up for drive motors controls and other train power needs through flexible brushes  35 ,  36 , and  37  (or more as required) which are connected to yoke  14 . Power supplied can be AC or DC as appropriate and depends on the drive used whichever is considered most efficient by those skilled in the art of such drives. Conventional overhead (over fuselage  38 ) power connections can also be used (not shown).  
         [0042]     To minimize aerodynamic drag forces, which are the forces that mainly govern how much drive power is required, it&#39;s desirable to design the train fuselage  38  only wide and tall enough to accommodate standard cargo containers or passengers (a possible passenger unit width is shown). How to hinge the upper roof portion so cargo containers, such as ship containers or truck containers, can be craned or lowered in are well known and are not a part of the teachings of this invention but would be well known by those in the art but could be a cam-locked roof or cap assembly (not shown) atop  38  etc. As shown in  FIG. 1 , the train has a scale of 1 inch equals 36 inches.  
         [0043]     This invention allows for standard gage switching technology to be used, either elevated or at ground level. If a rural situation where ground level load changing is needed, it would be a fence enclosed station and switching area and the train would switch using conventional track switching technology and travel down a ramp into a ground station area from the elevated track system depicted in  FIGS. 1 and 2 . Thus  FIG. 3  depicts an elevated high-speed switching and city terminal system. Train module  39  is just entering from elevated main track  40  (elevated from ground level  40 ′ as shown) up lowered ramp  41  which is raised and lowered by cable crane unit  42 . The terminal  43  would have a complement of buildings  43 ′ and track switching as needed including a control tower, ticketing and luggage handling, automated elevator car garages, cargo handling areas, hotels, helicopter pads and more. Such ramp  41  or conventional switching technology (not shown) off main track  40  into terminals can be used. Once train module  39  is in the terminal, conventional standard gage switching systems can direct it to any number of terminal offloading locations either under battery power or it can be pulled around like planes in airports. Train module  44  is seen launching from the terminal down ramp  45  lowered by cable crane  46 . Ramp  45  is also wired to power to accelerate the train to nearly full speed (about 100 MPH in terminal through areas, leaving). The dotted line  47  represents the ramp  45  in a raised position so trains can pass under the terminal  43  at high speeds. The speed of train module  39  entering ramp  41  should probably not exceed, say, 40 MPH, although safety net  48  with actuator and supports shown, the net represented by dotted lines  49 , would always be deployed as a train enters up-ramp  41  as emergency train stop in case braking failed. Safety stopping net  49  would typically be stored in a hanging vertical position  50  ready for rapid deployment by pulling down to ground level as shown (mechanism not shown). Ramp switching enables side-by-side through-lines to remain in place with the same line spacing, and switching trains don&#39;t cross multiple track systems to switch to a new destination or into the terminal. Other advantages of ramp switching are assisting with deceleration and acceleration. However, whether rail lines are elevated or at grade, conventional switching is also fully applicable to this train system.  
         [0044]     While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention as defined in the appended claims.