Abstract:
A magnetically levitated transportation system employs permanent magnet rails along a guideway that interact with permanent magnets on a vehicle. The rails are optimized to reduce magnetic mass and cost of materials, while maximizing lift force. The vehicle is stabilized in the lateral and yaw directions with feedback controlled lateral control coils that interact with the permanent magnet rails on the guideway. A track switching structure employs permanent magnet rails that gradually widen along a segment of track and separate into two identical diverging rails. Feedback controlled lateral control coils in a moving vehicle stabilize that vehicle over one or the other pairs of diverging rails, as directed by a control computer, thereby causing the vehicle to continue along one path or the other, with no moving or active elements required in the track.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
   Embodiments of the present invention relate to U.S. Provisional Application Ser. No. 60/850,182, filed Oct. 10, 2006, entitled “Track Switching for a Magnetically Levitated Transportation System and Method”, the contents of which are incorporated by reference herein and which is a basis for a claim of priority in the current application. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates, generally, to transportation systems and processes, and in particular embodiments, to ground-based transportation systems and processes employing magnetically levitated vehicles for transportation of freight or passengers. Certain embodiments are configured for relatively low-cost and energy efficient implementations. 
   2. Background of the Disclosure 
   Transportation of freight and passengers can be necessary in the modern economic society. During the current and previous centuries significant advances have been made with respect to the speed and efficiency of transportation systems. Such advances have been driven, at least in part, by economic demand. Indeed, high-speed transportation of freight and passengers has long been recognized as having significant economic value. This is evidenced by the widespread use of air transportation and increasing use of high-speed rail in both freight and passenger markets. 
   Conventional high-speed rail systems can require mechanical contact between wheels and rail, giving rise to vibration, noise, wear, and frictional losses of energy. Air transportation requires the high costs of pilots, air traffic control systems, airports and an even larger expenditures of energy. 
   Past efforts to address some of those shortcomings have included efforts to develop magnetically levitated train systems. Prototypes of such systems have been constructed that would require costly infrastructure in the form of heavy and precise track systems or expensive superconducting magnets. In some prior systems, massive trains have been proposed, requiring massive, expensive infrastructure. In addition, prior systems have employed relatively complex geometries, due to a perceived necessity to provide horizontal surfaces to create levitation forces and vertical surfaces to create lateral forces. Moreover, since electromagnets can only generate attractive forces, some proposed systems have included vehicles configured with awkward and heavy structures that reach underneath an iron rail to create lift. 
   A common feature of many such prior designs is that the vehicle structure wraps partially around the track structure or the track structure wraps partially around the vehicle structure. Such structures can be complex and massive, as they support high loads applied to cantilevered substructures. An indication of the complexity of these systems is that there is no single plane that separates the vehicle magnetic components from the track magnetic components. This follows from the use of both vertical and horizontal magnetic gaps in such designs. These structures are not only large and expensive, but also make track switching slow and cumbersome, compromising the potential for speed and convenience offered by maglev systems. 
   A railroad switch, or turnout, is a mechanical installation enabling trains to be guided from one line of rail tracks to another. In a typical installation, rail track “A” divides into two tracks, “B” and “C”. At the bifurcation point, a switch contains a pair of linked tapering rails (point blades) that can be moved laterally into one of two positions, determining whether a train coming from “A” will be led towards “B” or towards “C”. Likewise, in order to allow maglev vehicles to be directed along varying transportation routes, some type of mechanism must be provided that is capable of switching the vehicle from one guideway to another. In some maglev systems, such as the German Transrapid and the Japanese Railway MLX-01, this mechanism involves physically displacing a large guideway segment in order to redirect the maglev train. 
   U.S. Pat. No. 3,964,398 (titled “Magnetic-suspension vehicle system having switch tracks”) to Breitling, describes a magnetic-suspension vehicle system in which a vehicle is displaceable along a track provided with armature rails which cooperate with electromagnets carried by the vehicle to suspend the latter from the track. Switch locations provided along the track and the rails in these regions are designed to allow crossover of the electromagnetic arrangement on each side of the vehicle between main and auxiliary rails. The main and auxiliary rails are shaped to prevent mutual interference at the crossover points or their junction sites at a common side of the vehicle. 
   U.S. Pat. No. 5,517,924 (titled “Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching”) to He, et al. describes a stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with superconducting magnets mounted on the magnetic levitation (maglev) vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 
   U.S. Pat. No. 5,865,123 (titled “Electromagnetic induction suspension and horizontal switching system for a vehicle on a planar guideway”) to Powell, et al. describes an electromagnetic induction suspension and horizontal switching system for a vehicle on a substantially planar guideway that provides vertical lift and stability and lateral stability for a vehicle, including pitch, yaw and roll stability. The suspension and stabilization system allows electronic, horizontal switching between multiple substantially planar guideways such as a mainline guideway and a secondary guideway, which may be accomplished at speeds over 300 m.p.h. Proximal to and within a switching area at the intersection of the mainline guideway and the secondary guideway, the respective lift and stability systems for each guideway coexist and may be switched on or off, depending on the path chosen for the vehicle. 
   SUMMARY OF THE DISCLOSURE 
   Embodiments of the present invention relate, generally, to magnetic levitation transportation systems and methods, for example, but not limited to those as described in U.S. Pat. No. 6,684,794, and further including track switching configurations for such magnetic levitation transportation systems. For example, embodiments of the invention, relate to a guideway formed in part from permanent magnet rails that gradually bifurcate into two track paths. Permanent magnets can be employed on a vehicle for providing (or contributing to) levitation of the vehicle over the magnet rails, and electromagnets can be employed on the vehicle for providing (or contributing to) lateral control of the vehicle relative to the magnet rails and controlling the lateral position of the vehicle along one bifurcation or the other. An additional advantage available in the embodiments of the current invention can be the lack of a need for moving or active elements in the guideway of the present invention. In addition, embodiments of the invention may provide an ability of a vehicle to cross a switching section at any speed, from barely moving up to a very high maximum speed. 
   One embodiment of the current invention relates to a transportation system that includes at least one original guideway having a length dimension and at least one array of permanent magnets extending along the original guideway length dimension. The original guideway can bifurcate into a first and a second guideway. This system embodiment can also include one or more vehicles, where each vehicle has at least one permanent magnet array arranged to magnetically interact with the at least one array of permanent magnets on the guideway. The vehicle can travel along the length dimension of the guideway. This embodiment further includes at least one electromagnetic coil for selecting either the first or the second guideways. In another embodiment, the permanent arrays can be arranged in a Halbach array formation. In another embodiment of the current invention, the first and second guideways have the same permanent magnet array formation as the original guideway. 
   In another embodiment, the vehicle can include a magnetic assembly that comprises, two electromagnetic coils and one magnet array in Halbach formation. Another embodiment, includes a magnetic assembly coupled to the vehicle using a rotatable pivot. 
   In yet another embodiment, two magnetic assemblies can be coupled to each other using a structure element and the structure element can be coupled to the vehicle using a rotatable pivot located at the center of the structure element. In another embodiment, the electromagnetic coils can be arranged in a series or a parallel formation to produce lateral forces for magnetic interaction with the at least one guideway. 
   Another embodiment, includes a controller for controlling the direction and the magnitude of a current in the electromagnetic coils. The controller can exert lateral magnetic forces on the guideways to move the vehicle in a right or a left direction. The controller receives feedback signals related to lateral position of the vehicle at any given time and compensates by adjusting the current in the electromagnetic coils for speed and turn radius of the guideway. 
   Another embodiment can include a crossing zone, where the first and second guideways bifurcate from the original guideway. The crossing zone can include additional permanent magnets to provide sufficient levitation for the vehicle in transition and to duplicate the original guideway. In another embodiment, the additional permanent magnets can increase in size to provide additional magnetic force. 
   Another embodiment of the current invention is related to a bifurcating track for magnetic levitation trains. The track can include at least one guideways having a length dimension and at least one array of permanent magnets extending along the guideway length dimension. The track may further include a second and a third track that bifurcates from the first track via a crossing zone. The second and third track can each have at least one guideway where each guideway has a length dimension and at least one array of permanent magnets extending along the guideway length dimension. The crossing zone can include additional permanent magnets to provide sufficient levitation for the vehicle and to duplicate each guideway. In this embodiment the permanent magnets can be arranged in a Halbach formation. 
   In another embodiment of the bifurcating track the additional permanent magnets increase in size to provide additional magnetic force. 
   Another embodiment of the current invention relates to a control system for controlling the lateral movement of a magnetic levitation transportation vehicle. The control system can include a plurality of sensors that provide information related to a maglev vehicle to the controller. The controller can receive signals from the sensors and generate signals for the amplifiers that can generate current to be applied to the stabilization coil coupled to the maglev vehicle. The stabilization coil in this embodiment can produce sufficient magnetic flux to interact with a guideway and create lateral movement in the vehicle. 
   These and other aspects and advantages of embodiments of the present invention will become apparent from the following detailed description and the accompanying drawings in which various embodiments of the present invention are shown by way of illustrative example. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1   a  shows a cross-sectional schematic representation of a magnetic levitation vehicle suspended above magnet rails embedded in a road bed. 
       FIG. 1   b  shows a bottom view of the maglev vehicle of  FIG. 1   a.    
       FIG. 2   a  shows a bottom cross-sectional view of the vehicle magnet assembly of  FIG. 1   a.    
       FIG. 2   b  is a cross-sectional view of vehicle and track magnet assemblies from  FIG. 2   a.    
       FIG. 3  shows a top view of a general configuration of magnet rails as they bifurcate for track switching according to an embodiment of the present invention. 
       FIG. 4  (A-G) shows a cross-sectional view of the vehicle of  FIG. 1  as it progresses through the track bifurcation of  FIG. 3 . 
       FIG. 5  (A-L) shows close-up cross-sectional views of one vehicle magnet assembly and one track magnet assembly, as the vehicle progresses through the track bifurcation of  FIG. 3 . 
       FIG. 6  shows a block diagram representation of a control system for the track switch and transportation system. 
       FIG. 7   a  shows a top view of the general configuration of magnet rails as they bifurcate for track switching according to a another embodiment of the present invention. 
       FIG. 7   b  shows an enlarged view of the track crossover from  FIG. 7   a.    
       FIG. 8  shows a top view of a double slip track switch according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following detailed description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles and various embodiments of the invention. The present invention relates, generally, to transportation systems and processes, and in particular embodiments, to such systems and processes for magnetically levitated vehicles for transportation of freight or passengers. A transportation system, according to embodiments of the invention, includes at least one vehicle and a guideway along which the vehicle is capable of traveling. In preferred embodiments, the vehicle is capable of carrying freight or passengers and includes one or more compartments or supports for holding freight or passengers. 
   As described in further detail below, the vehicle can have one or more magnets (or arrays of magnets) and one or more electromagnets for providing levitation and lateral control functions. The magnets (or magnet arrays) may comprise any suitable permanent magnet or magnetized material having a relatively large intrinsic coercivity, including, but not limited to well known alloys of neodymium-iron-boron, ferrite, samarium-cobalt, or the like. The electromagnets may comprise electromagnetic coils or other suitable structures for creating an electromagnetic field. 
     FIG. 1   a  shows a cross-section of a magnetic levitation system  10 , including a maglev vehicle  20  that can be suspended above magnet rails  12  embedded in roadbed  14 , for example, in a manner as described in U.S. Pat. No. 6,684,794, titled “Magnetic Levitation Transportation System And Method,” to Fiske, et al., the disclosure of which is incorporated herein by reference. Roadbed  14  may comprise a road-like structure, an elevated structure, an underground tube or tunnel structure or other suitable guideway or path for supporting magnet rails  12 . Further example embodiments of the invention employ guideway structures of the type described in U.S. Pat. No. 6,684,794. Each vehicle magnet array  16  may comprise, for example, a Halbach array formation, and may be mounted in a magnet assembly  24 , to produce magnetic fields toward the roadbed  14 . Magnet rails  12  include magnet arrays that can be arranged, for example, in Halbach arrays, to produce complementary magnetic fields directed upward, toward the vehicle. In combination, vehicle magnet array  16  and magnet rails  12  can create a powerful repulsive force that acts to levitate the maglev vehicle  20 . In this configuration, levitation can be vertically stable (repulsive force increases as the gap between vehicle and track decreases, and vice-versa), but further laterally stability may be desired. Lateral forces can be zero when vehicle magnet array  16  is centered above magnet rails  12 , but increase as maglev vehicle  20  moves laterally to one side or the other with respect to magnet rails  12 . 
   The relative lateral position of vehicle magnet array  16  and magnet rails  12  is monitored by position sensors  200  shown in  FIG. 6  in a block diagram. A control computer controls the application of electrical current from an amplifier  220  through stabilizing coil set  18 . The stabilization coil set  18  can be made of, for example, electro-magnetic material, magnets that can be physically moving or rotating or material with varying magnetic intensity. The stabilization coil set  18  can be mounted at various location on the vehicle, such as but not limited to, below vehicle magnet array  16 , to create magnetic fields that interact with magnet rails  12  to produce lateral magnetic forces. This interaction can create a feedback loop that counteracts unwanted lateral motion and can stabilize the lateral position of maglev vehicle  20 . As will be explained below, this stabilizing action can be used to control the maglev vehicle  20  in a manner to effectively “steer” the maglev vehicle along one or the other track when a track bifurcates in two different directions. 
     FIG. 1   b  shows one example embodiment, with four magnet assemblies  24   a ,  24   b ,  24   c  and  24   d . In this example embodiment each maglev assembly includes two stabilizing coil sets  18 , but in other embodiments the magnet assembly can include one or any suitable number more than one coil sets. Magnetic assemblies  24   a  and  24   b  show one example placement for pivot joints  30   a , such as, but not limited to pivotal truck structures, pivot pins or the like, for pivotally joining the magnetic assemblies to another portion of the vehicle  20 . The pivot joints  30   a  allow the maglev assemblies to follow a curved track or switch tracks by allowing the maglev assemblies to pivot about the axis of a pin, joint or the like (for example, the central axis of the circle representing the pivot joints  30   a  and  30   b  in  FIG. 1   b ). An alternative arrangement of a pivot joint  38  is shown with respect to the magnetic assemblies  24   c  and  24   d , where the pivot  38  is mounted on structural element  36  connecting the two magnetic assemblies  24   c  and  24   d . Pivots  30   a ,  30   b  and  38  allow the magnetic assemblies  24  to rotate about a rotation axis (an axis arranged into and out of the page in  FIG. 1   b ), to allow the magnetic assemblies to better follow curved tracks and decreasing the minimum turn radius of maglev vehicle  20 . 
     FIG. 2   a  illustrates part of a vehicle magnet assembly  24  of  FIG. 1   b , showing left stabilization coil  18   a  and right stabilization coil  18   b  as they relate to vehicle magnet array  16 . The vehicle magnet assembly  24  can provide sufficient magnetic force while using one or more stabilization coils. In other embodiments, the coils can be in either series or in parallel to each other. In yet other embodiments, a coil is not necessary, where a magnetic force generator that generates magnetic flux can be controlled with precession and interacts with the magnetic rails  12 . 
     FIG. 2   b  shows one embodiment of a cross-sectional view of magnetic assembly  24 , taken along line A of  FIG. 2   a . Included in  FIG. 2   b  is magnet rail  12 , showing polarities of magnets in the rail array (for example, the arrowhead indicates North and the non arrowhead indicates South) and relative sizes of each of constituent magnets  12   a ,  12   b  and  12   c . The size of the permanent magnets used for the arrays can vary, based upon a variety of factors such as but not limited to the weight, and size of the vehicle. Vehicle magnet array  16  can be one or more magnet components, and magnet rail  12  can be made of at least three magnet components, other arrangements such as but not limited to six vehicle magnets and four magnetic rail magnets are possible. The magnets in each array can be in an orientation such that the magnetic flux points primarily in one direction for each array. 
   The stabilizing coil set  18  includes left coil  18   a  and right coil  18   b . In normal operation, vehicle magnet array  16  is suspended at an unstable equilibrium point centered over track magnet element  12   b . One embodiment the stabilization coils  18   a  and  18   b  has current flowing through them creating sufficient magnetic flux necessary to change the lateral direction of the maglev vehicle  20 . The magnetic flux generated by the stabilization coils  18   a  and  18   b  can be controlled by a controller that will be discussed in greater detail below, referring to  FIG. 6 . 
     FIG. 3  illustrates a top view of maglev track switch  50 , showing a configuration of a roadbed  14  and magnet rails  52  and  54  as they bifurcate for track switching according to the embodiments of the present invention. While  FIG. 3  shows one example track switch, there are many varieties of track switches that can be implemented using embodiments of the current invention. Other types of track switches include for example, but are not limited to, Double slip, Single slip, Crossover, Stub switch, Plate switch, Three-way switch, Interlaced turnout, Wye switch, Derailers and Switched diamond. 
   In  FIG. 3 , magnet rails  52  and  54  gradually widen, then split into two identical rails. Magnet rail  52  splits into rails  52   a  and  52   b , while magnet rail  54  splits into rails  54   a  and  54   b . The length of this bifurcation zone is related to the highest speed at which the vehicle is allowed to transit the switch, and can be short (on the order of a few meters or less) if the vehicle transits at low speed, or long (hundreds of meters or more) if the vehicle can transit at high speed. Magnet rails  52   b  and  54   a  converge into combined rail  56  in a “crossing zone”, and thereafter diverge again to complete the track switch bifurcation, with magnet rails  52   a  and  54   a  continuing on roadbed  14   a , and magnet rails  52   b  and  54   b  continuing on roadbed  14   b . The further track formed from rails  52   a  and  54   a  is similar in configuration to the original track and the further formed track from  52   b  and  54   b  is similar in configuration to the original track. Lines A through G provide reference points for roadbed and track cross sections illustrated in the following figure, as discussed in greater detail below. 
     FIGS. 4  (A-G) show cross-sectional views of the vehicle of  FIG. 1  as it progresses through the track bifurcation of  FIG. 3 .  FIG. 4A  corresponds to line A of  FIG. 3 ,  FIG. 4B  corresponds to line B of  FIG. 3 , and so on. In  FIG. 4A , maglev vehicle  20  is moving over roadbed  14  including magnet rails  52  and  54 . In  FIG. 4B , the roadbed has widened slightly, magnet rail  52  bifurcates into rails  52   a  and  52   b , likewise magnet rail  54  bifurcates into rails  54   a  and  54   b , and maglev vehicle  20  has moved rightward to follow track b. In  FIG. 4C  the roadbed has further widened, the magnet rails have further separated, and maglev vehicle  20  has moved further to the right. In  FIG. 4D , the roadbed has widened even further, while magnet rails  52   b  and  54   a  have nearly converged. In FIG.  4 E, magnet rails  52   b  and  54   a  have completely converged to form a combined rail  56  or a crossing zone and the maglev vehicle  20  is above rail  56 . In  FIG. 4F , magnet rails  52   b  and  54   a  have diverged again, and the roadbed is approaching its greatest width. In  FIG. 4G , the roadbed has diverged into separate guideways  14   a  and  14   b , with maglev vehicle  20  continuing on track b. When traversed in the opposite sequence, starting with  FIG. 4G  and ending with  FIG. 4A , this also depicts the progress of a vehicle through the intersection of two guideways. In other words, the vehicle can transit the track bifurcation in either direction. 
     FIG. 5A-L  depicts a cross-sectional view of a vehicle magnet array  16  with a pair of stabilization coils  18   a  and  18   b  from the vehicle of  FIG. 4 , and a bifurcating rail magnet array from the track of  FIGS. 3 and 4 . In this embodiment, the polarities and relative cross-sectional areas of the magnets in each array are shown, as is the current flow direction in the stabilization coils. When produced in the directions shown, current flow in the stabilization coils  18  results in a rightward force on the maglev vehicle  20 . The force can “steer” the vehicle on the track located on the right. If the current directions in the coils were reversed, a leftward force could be produced on the vehicle, and the vehicle could steer to the left through the bifurcation. 
   In  FIG. 5A , the vehicle is progressing along a guideway prior to reaching a track bifurcation.  FIG. 5A  shows the vehicle magnet array  16  centered over magnet rails  12 , as it would be in a straight section of non-bifurcating track. In this embodiment, magnet rail  12  is composed of three magnets,  12   a ,  12   b  and  12   c , with polarities as indicated. However, with other configurations more or less magnets can produce similar results. Current direction and intensity is adjusted through the vehicle stabilization coils  18   a  and  18   b  by the stabilization control system shown in  FIG. 6  to keep the vehicle centered over the track. 
   In  FIG. 5B , the vehicle has moved into the start of a track bifurcation. In general, bifurcation requires adding new track magnet elements and modifying the size of existing track magnet elements such that the vertical suspension force on the vehicle and the suspension stiffness remain nearly constant while giving the vehicle two possible paths of travel. In this one embodiment, while traveling along the bifurcation the center magnet  12   b  is replaced by two magnets  60   c  and  62   c , two new magnets  60   d  and  62   d  is inserted into the between  60   c  and  62   c , and two new magnets  60   a  and  62   a  can be added to each end of the array for a total of eight magnet components. The bifurcating track magnets thicken by up to four times the original rail, in the vertical dimension, to compensate for reduced vertical force caused by the split. Track magnet components  60   a ,  60   b ,  60   c  and  60   d  now provide one path for the vehicle, with an unstable equilibrium point above magnet  60   c . Track magnet components  62   a ,  62   b ,  62   c  and  62   d , which form a mirror image of  60   a - d , provide the second path, with an unstable equilibrium point above magnet  62   c . Vehicle magnet array  16  is centered over magnet rails  60   a - d  and  62   a - d , at an unstable equilibrium point centered above magnet elements  60   d  and  62   d , with vehicle stabilization coils  18   a  and  18   b  energized as needed to maintain that position. 
   In  FIG. 5C , the maglev vehicle  20  has moved further into the track bifurcation. Track magnets  64   a - 64   d  and  66   a - 66   d  have the same configurations and polarities as  60   a - 60   d  and  62   a - 62   d , respectively, but the magnets can have a cross-sectional area that is up to four times larger than in  FIG. 5B . The bifurcating track magnets thicken by up to four times the original rail, in the vertical dimension and horizontal direction, to compensate for reduced vertical force caused by the bifurcation. 
   In  FIG. 5D , the maglev vehicle  20  continues further into the track bifurcation. Track magnets  68   a - 68   d  and  70   a - 70   d  are changed in dimensions or cross-sectional area by up to four times the original magnet dimensions. Current is applied by the controller as shown in  FIG. 6  to the stabilization coils  18   a  and  18   b  (connected in parallel or series) to provide a rightward-directed force. The current directions shown in  FIG. 5D  produce the rightward force. The magnitude of the current affects the speed at which the switch may be traversed by the maglev vehicle  20 . The greater the magnitude of the current the faster the switch may be traveled by the vehicle. 
   In  FIG. 5E  the maglev vehicle  20  has progressed further into the bifurcation and has begun to respond to the rightward force created by the stabilization coils  18   a  and  18   b . Vehicle magnet array  16  is now displaced to the right of the center of the track. Track magnets  72   a - 72   d  and  74   a - 74   d  can be up to four times larger in size or cross-sectional area than track magnets shown in  FIG. 5B . The size of the magnets can vary depending on the vehicle weight and size and the amount of current being used. 
   In  FIG. 5F , as the maglev vehicle  20  has progressed further into the bifurcation, vehicle magnet array  16  is displaced further to the right of the center of the track magnet array. As shown in  FIG. 5F , the track magnets can increase in cross sectional area by up to four times the magnets in  FIG. 5B , to provide greater magnetic levitation. 
   In  FIG. 5G , the maglev vehicle  20  has progressed further into the bifurcation. Vehicle magnet array  16  is displaced further to the right of center of the track magnet array. The track magnets have thickened again by up to 4 times the magnets in  FIG. 5F , to provide magnetic levitation.  FIG. 5G  shows track magnets  76   a - 76   d  and  78   a - 78   d  with the same polarity as the magnets is  FIG. 5F , but the cross sectional area of these magnets can be five times the size of the track magnets shown in  FIG. 5G . 
   In  FIG. 5H , the maglev vehicle  20  continues its forward motion, vehicle magnet array  16  is displaced further to the right of the original track due to the force applied to the stabilization coils  18   a  and  18   b . The track magnets have reached their maximum dimensions and cross-sectional area in  FIG. 5H , and can be up to four times the size of the magnets shown in  FIG. 5B .  FIG. 5H  shows larger track magnets  80   a - 80   d  and  82   a - 82   d  with the same polarity as the magnets is  FIG. 5G . 
   In  FIG. 5I  the maglev vehicle  20  has moved further and vehicle magnet array  16  is displaced further to the right of center of the original track. Track magnets  84   a - 84   d  and  86   a - 84   d  are narrower than magnets  80   a - 80   d  and  82   a - 80   d.    
   In  FIG. 5J , the maglev vehicle has moved forward and is displaced further to the right of center of the original track. Vehicle magnet array  16  is centered over the right half of the bifurcating track, at the unstable equilibrium position above track magnet  90   c , and the track magnets have decreased in both width and thickness. 
   In  FIG. 5K  the vehicle has continued forward and is displaced further to the right of center of the original track. Track magnets  92   a - 92   c  are similar in dimensions to the corresponding elements of a single magnet track, such as track magnets  12   a - 12   c  in  FIG. 2   b . Track magnets  94   a - 94   c  are similar to magnets  92   a - 92   c . Vehicle magnet array  16  is slightly to the right of the unstable equilibrium position above track magnet  94   b , thereby compensating for the leftward centripetal force caused by the vehicle&#39;s motion along the rightward turning track. 
   In  FIG. 5L  track bifurcation is completed. Track magnets  96   a - 96   c  and  98   a - 98   c  can be identical to track magnets  12   a - 12   c  in  FIG. 2   b , i.e. they can have the same dimensions as the track magnets in a non-bifurcating track segment. Vehicle magnet array  16  is slightly to the right of the unstable equilibrium position above track magnet  98   b  to compensate for leftward centripetal force from the turn. If the maglev vehicle  20  had steered to the left, rather than the right, the same sequence of events would occur, but with leftward forces from the stabilization coils and leftward motion of the vehicle magnet array  16  and the maglev vehicle  20 . 
   With this system, a track bifurcation may be traversed in either direction. In other words, a vehicle may travel from a single track onto either of two tracks, as shown above, or may travel along either of two tracks leading into an intersection, and onto a single track leading out of the intersection. 
   In the embodiment illustrated in  FIG. 5A-L , both sides of the track bifurcation are curved, one to the left and the other to the right. In other embodiments, one side of the track bifurcation could be straight, allowing the other side to form a turnout as required for an off-line station or side track, for example. Although specific magnet configurations and dimensions are shown, other configurations and dimensions can be employed to achieve similar results. 
     FIG. 6  illustrates a block diagram of a lateral controller  210 . The controller receives signals corresponding to the lateral position of the maglev vehicle  20  in relation to the track magnets at all times in order to adjust the current to the stabilization coils  18   a  and  18   b . The information that is used by the controller  210  can be provided by sensors  200  that can be placed on the vehicle, rails and/or the magnet arrays. The sensors  200  provide feed back signals such as but not limited to speed, lateral position of the vehicle relative to the track and position of the vehicle in the direction of motion relative to a track bifurcation. The controller  210  adjusts the magnitude and the direction of the current in stabilization coils  18   a  and  18   b . In an alternative embodiment, the controller  210  can also control servo motors or other devices cable of adjusting the pivot joints  30   a ,  30   b  or  38  depending on the turn radius an speed of the vehicle. Each maglev assembly  24  can have its own lateral controller  210  and associated sensors or each pair of maglev assemblies can share a controller and associated sensors. In another embodiment, a single controller and associated sensors can control all of the maglev assemblies. 
     FIG. 7   a  illustrates a top view of maglev track switch  100 , showing a configuration of a roadbed  106  and magnet rails  102  and  104  as they bifurcate for track switching according to another embodiment of the present invention. In this embodiment, magnet rail  102  bifurcates at bifurcating point  108 , splitting into curved rail  112  and straight rail  114 . Likewise, magnet rail  104  bifurcates at  110 , splitting into curved rail  116  and straight rail  118 . Rather than converging with rail  116 , straight rail  114  includes crossover gap  120 , which consists of a gap in rail  114  through which curved rail  116  passes. In this embodiment of the current invention, the maglev vehicle  20  can travel along the maglev track switch  100 , in a similar manner as described in  FIGS. 4 and 5 . 
     FIG. 7   b  is a magnified view of crossover  120 . Straight rail  114  includes magnet elements  114   a ,  114   b  and  114   c . Similarly, maglev rail  116  includes magnet elements  116   a ,  116   b  and  116   c . Crossover gap  120  in straight rail  114  allows curved rail  116  to pass through. Outline  122  indicates the one possible length of a vehicle magnet array, showing how it overlaps crossover gap  120 . The vehicle magnet array can be considerably larger than gap  120 , only a fraction of the usual levitation force is lost as the vehicle passes over the gap, and does not appreciably effect maglev vehicle  20  levitation. 
     FIG. 8  is a top view of a double slip maglev track switch  130 , indicating how track bifurcations and crossovers can be used to create more complex switching arrangements. One track, comprising parallel maglev rails  132  and  134 , intersects a second track, further comprising parallel rails  136  and  138 . Track switch  130  includes rail bifurcations  140 ,  142 ,  144 ,  146 ,  150 ,  152 ,  154  and  156 . Track switch  130  also includes crossovers  160 ,  162 ,  164  and  166 . A vehicle traveling on rails  132  and  134  (from either direction) can pass straight through switch  130 , without changing tracks, or instead, can turn onto rails  136  and  138 . Similarly, a vehicle traveling on rails  136  and  138  can pass straight through switch  130 , or can turn onto rails  132  and  134 . In this embodiment of the current invention, the maglev vehicle  20  can traverse the double slip maglev track switch  130  in a similar manner as described above regarding  FIGS. 4  (A-G) and  5  (A-L). 
   The guideway need not contain any moving parts, control coils, or active elements of any kind. Because the vehicle is magnetically suspended and not in contact with the magnet rails or any other part of the guideway, and the switch uses no moving mechanical elements, embodiments of the present invention can provide an extremely robust, durable system with little or no wear. Also, the lack of moving or active elements in the guideway allows vehicles moving in close proximity along the guideway to change direction at intersections without regard to the direction chosen by the vehicles ahead or behind them.