Abstract:
A system for loading, unloading and rail transportation of road-hauled semi-trailers, having multiple wagons ( 1 ) constituting a railway train, with each of them incorporating at least one pivotable turntable ( 14 ) for accommodating a semi-trailer via its wheel assembly. The system also comprises a detachable hitch mounting ( 9 ) that can be gripped by a handling machine which carries the detachable mounting and assembles it, after adjustment on the semi-trailer&#39;s pivoting turntable. The hitch mounting is assembled on an accommodating platform ( 8 ) that is secured immobile to the wagon chassis ( 2 ) and independently of the pivoting turntable, in order to support the front of the semi-trailer during rail transportation. This invention is of interest to rail carriers and railway transport equipment manufacturers.

Description:
This application is a National Stage completion of PCT/IB2011/053322 filed Jul. 26, 2011, which claims priority from French patent application serial no. 10/03235 filed Jul. 30, 2010. 
     FIELD OF THE INVENTION 
     The present invention relates to a universal system for loading/unloading and rail transportation of road-hauled semi-trailers. 
     BACKGROUND OF THE INVENTION 
     To limit the size of roads and highways as well as the pollution generated by road transport, it is increasingly desired to expand the rail transportation of semi-trailers on specific wagons, and to transport them over long distances by rail rather than via the road network. 
     For this, semi-trailers must now be loaded and unloaded using different techniques in combined road and rail terminals specially equipped for performing such operations. Special and expensive infrastructure must be provided on railway platforms for the loading and unloading of these semi-trailers. 
     In addition, the trains used for such transportation are also very specific. They consist of specialized wagons for transporting this type of load and, in addition, must open so as to allow the loading and unloading of semi-trailers. These wagons are complex and also very expensive. 
     Various opening systems are known for these specialized wagons. One possible technique is to use wagons consisting of a rolling base and a bearing railway structure capable of being separated from its rolling base by pivoting; this pivoting can be central or can take place at one of its extremities. 
     Central pivoting provides the possibility of access or removal at one or other of the extremities, whereas pivoting around one of the extremities only leaves one end free for the entrance and exiting of semi-trailers before and after their transportation. 
     Other opening methods are also possible, such as—for example—sideways movement of the bearing railway structure. 
     All these systems have the disadvantage of being complex and expensive. 
     The specialized wagons have to be motorized and must be able to provide the energy required for their opening and closing movement while their bearing structure is loaded with semi-trailers. In addition, these specialized wagons must be equipped with additional specific trackside installations in specialized stations for the loading and unloading of semi-trailers. 
     All these necessary investments in wagons and trackside infrastructure explain the slow development of use of rail transport for semi-trailers, notwithstanding its desirability from the social, ecological, economic and political viewpoints. 
     Some systems of loading and unloading semi-trailers on to and from a wagon for rail transportation are already known. 
     First of all, there is U.S. Pat. No. 4,425,064 in the name of WALDA, concerning a turntable borne by the wagon and accommodating a semi-trailer&#39;s wheel assembly, and its securing to a mounting bearing a hitch. 
     This turntable pivots between a rolling position in which it is positioned within the longitudinal axis of the wagon, and a loading/unloading position in which it is rotated in relation to the wagon. 
     Towards the front, the wagon also comprises a platform bearing an articulated assembly composed of oblique arms articulated on the extremities, on which there is a semi-trailer hitch supporting the front of a semi-trailer by its kingpin. The articulated arms are conrods of which the inclination allows the hitch to change from a low resting position to a raised position for supporting the semi-trailer by its front section during its railway transportation. 
     While this invention does indeed include a pivoting bearing structure on the wagon, intended to accommodate the semi-trailer&#39;s wheel assembly, the hitch articulated on the elevation assembly is not detachable as for the present invention and, therefore, cannot be manipulated by a handling plant, and is not usable placed on the semi-trailer in view of adjustment and its installation on the wagon. 
     There is also the invention described in European patent EP no. 1712444 in the name of ARBEL FAUVET RAIL. 
     According to this patent, the semi-trailer is loaded into a load-bearing nacelle  4 , and it is immobilized on it laterally by means of fastening systems  24  and  25  and, at the front, by means of the restraining system  6  of the coupling  7 . The load-bearing nacelle  4  bears upon and is affixed to the long beams of the longitudinal edges of a wagon of the type referred to as a ‘pocket wagon’. 
     The clamping system  6  of the coupling  7  is combined into a supporting system  1  that is detachable from the nacelle  4  via a longitudinal sliding movement at the end of its deck. This supporting system  1  comprises a hitch secured at the top, which interoperates with the semi-trailer&#39;s kingpin. 
     To be operational, the supporting system  1  has to be assembled at the front end of the nacelle. A controlling system allows one to adjust the hitch heightwise. 
     However, only the supporting system is removable with a simple longitudinal separating movement, and one can only adjust the height of the hitch when this supporting system is in place, which seriously complicates the operations of positioning and supporting the front of the semi-trailer, and of loading it on to and unloading it from the wagon. 
     Lastly, through the publication DE 3234375 in the name of WAGGON FABRIK TALBOT, another system is known for loading and unloading a semi-trailer on to or from a wagon of type ‘pocket wagon’ type. This system includes a tipping and pivoting platform that accommodates the semi-trailer&#39;s wheel assembly and immobilizes it through controlled sinking within the wagon. The semi-trailer&#39;s kingpin is engaged within an elevation assembly allowing one to lift the front of the semi-trailer so that it can be supported by a support platform. The elevation assembly comprises the equivalent of a hitch, but it is not detachable and is not used for positioning the semi-trailer on the wagon by means of a handling plant. 
     All the difficulties of manoeuvring the semi-trailer are experienced at the moment of and during its positioning on the wagon and its removal from it. 
     SUMMARY OF THE INVENTION 
     The purpose of the present invention is to provide a system for loading/unloading and rail transportation for semi-trailers that is much simpler and less costly than current systems. 
     The wagons used are of very simple construction and are preferably non-motorized. Thus, they are much less expensive than prior means. 
     The system according to the invention requires no specialized trackside platform, nor any special trackside installation. Any station or area with a trackside platform can be used to load and unload semi-trailers. 
     The system does not need to be motor-driven and, therefore, requires no energy source on the wagon or on the trackside platform for loading/unloading. Only a handling machine such as a forklift truck is necessary for the loading or unloading of semi-trailers, and for switching the system from its loading/unloading position to the transportation position, and vice versa; this handling plant is very commonplace and forms part of the basic equipment of all stations used for cargo and freight transportation. 
     The system is also universal, namely it can be used for any kind of semi-trailer, regardless of its type, model and length, provided that it has a wheel assembly at the rear and a kingpin at the front; the distance between them can be different, according to the country and the road regulations in force. 
     In addition, it allows easy and quick loading and unloading. This is because all the semi-trailers transported by the system according to the invention can be loaded or unloaded one after the other, or simultaneously in groups, or all together, in any order, depending on the users&#39; preferences and/or the number of handling machines present. 
     To this end, the invention provides a universal system for loading/unloading and rail transportation of road-hauled semi-trailers, that includes at least one rail wagon forming part of a train, this wagon incorporating a chassis and designed to accommodate at least one road-hauled semi-trailer for its rail shipment, equipped with a kingpin at the front and a wheel assembly at the rear. 
     According to the invention, this wagon comprises:
         at least one bearing turntable which pivots in relation to the chassis that is suitable for accommodating the semi-trailer&#39;s wheel assembly; this turntable pivots between a transportation position in which it is positioned longitudinally in relation to the wagon, and a loading/unloading position in which it is oriented transversely or obliquely with respect to the wagon; and   at least one accommodating platform to support the semi-trailer&#39;s kingpin; this accommodating platform is connected to or integrated with the chassis, being fixed in relation to it and being independent of the pivoting turntable.       

     The system according to the invention also comprises a detachable hitch attachment incorporating:
         a body that can be gripped by a handling machine and which is assembled in a detachable manner on the wagon&#39;s accommodating platform; and   a hitch, preferably adjustable in height relative to the body, designed to accommodate and immobilize the semi-trailer&#39;s kingpin.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will be mentioned in the description which follows, provided by way of example, and the accompanying drawings, in which: 
         FIGS. 1 and 2  are respectively side and top plan views of a dual wagon with two pivoting turntables in the transportation position; 
         FIGS. 3 and 4  are respectively side and top plan views of a dual wagon with two pivoting turntables in the loading/unloading position; 
         FIGS. 5 to 7  are views of the hitch attachment, with: 
       for  FIG. 5 , a perspective view in isolation; 
       for  FIG. 6 , a side view as when assembled on an accommodating platform connected to the wagon chassis; 
       for  FIG. 7 , a top view as when assembled on an accommodating platform connected to the wagon chassis; 
         FIGS. 8 to 11  are respectively top and side views illustrating the assembly of the semi-trailer on the turntable when it remains coupled to its road haulage tractor; 
         FIG. 12  is a schematic side view illustrating the hitch attachment, illustrating the phase of height adjustment of the hitch; 
         FIG. 13  is a side view of the semi-trailer loaded on to a turntable, with its legs bearing on the trackside loading platform; 
         FIGS. 14 to 16  are top views of the system, illustrating the phases of installation of the hitch, pivoting of the turntable and mounting of the hitch attachment on the corresponding accommodating platform of the wagon, all of which is done with a forklift truck; 
         FIG. 17  is a side view of the trackside platform, showing the positioning of the hitch attachment on the corresponding accommodating platform of the wagon; 
         FIG. 18  is a schematic side view illustrating the hitch attachment, showing the phase of height adjustment of the hitch; 
         FIGS. 19 to 32  are pairs of views, respectively from above and the side, of the system according to the invention in the various stages of loading with a forklift truck, in the scenario in which the road haulage tractor does not assemble the semi-trailer on the turntable;  FIGS. 29 and 30  represent an alternative variant to  FIGS. 27 and 28 ; 
         FIGS. 33 and 34  are views respectively in perspective and from above, showing the wagon loaded with two semi-trailers and ready for departure; 
         FIG. 35  is a top view showing a wagon with pivoting accommodating plates with oblique transversal rims; 
         FIGS. 36 to 38  are schematic perspective views respectively showing the arrival of two semi-trailers in front of two pivoting turntables in oblique loading position, the loading of the semi-trailers on to these turntables by means of their road haulage tractor, and the departure of the road haulage tractor from the semi-trailers on the pivoting turntables. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The system according to the present invention will now be described in detail, with reference to  FIGS. 1 to 38 . Equivalent items shown in the various figures are assigned the same reference numerals. 
     The basic version of the universal system for loading/unloading and rail transportation of semi-trailers according to the invention comprises simple wagons  1  composed of a chassis  2 , preferably flat and lowered, of which this chassis is supported at each of its extremities by an end wheel assembly known as a bogie  3 . 
     The transportation system according to the present invention can also employ dual wagons  1 , such as those illustrated in the figures, each of which is formed by the combination of two basic wagons  4 . These dual wagons  1  then incorporate several types of bogies  3 : two end bogies  5  and one common intermediate bogie  6  that provide a median rolling bearing point between the basic wagons  4  positioned front to back. 
     The dual wagons have the important advantage of being able to carry two road haulage loads on one railway wagon. However, the invention applies to any type of railway wagon  1 , provided that it comprises a chassis  2  capable of carrying one or more semi-trailers and of bearing all the stresses generated by their transportation. 
     In the embodiment shown, each basic wagon  4  comprises a chassis  2 —preferably flat and lowered—assembled at one of its ends on the intermediate bogie  6  and, at its other end, assembled on the corresponding end bogie  5 . The two extremities of the dual wagon  1  are terminated by rail buffers and, in each case, a coupling hook  7 . 
     The wagons each incorporate—preferably near the end bogies  5 —an accommodating platform  8  that is fixed in relation to the chassis  2 , which constitutes one of the principal features of the loading and transportation system according to the invention. This accommodating platform  8  is designed to accommodate and bear a hitch attachment  9 , which is also another essential feature of the invention and which, as will be understood further on, is assembled in a detachable manner on the accommodating platform  8  during the loading of a semi-trailer, remains in place during its transportation, and is removed when unloading the semi-trailer. 
     For this, the accommodating platform  8  includes an immobilization system  10  that interoperates with the complementary immobilization system  11  borne by the hitch attachment  9 . 
     The immobilization system  10  of the platform can be of any type provided that it allows, in association with the complementary immobilization system  11  of the hitch attachment  9 , detachable securing and temporary restraining of the hitch support  9  on the accommodating platform  8 . The system can be fixed or detachable or articulated. 
     For example, It may be lugs  12 , pins, projections, fingers, hooks or other protruding elements interoperating with openings  13 , rings, hollows or cavities of whatever design held by the hitch attachment  9 . 
     Conversely, the immobilization system  10  of the accommodating platform  8  can be openings, rings, hollows or cavities of whatever design that interoperate with lugs, pins, projections, fingers, hooks or other protruding elements of the hitch attachment  9 . 
     These immobilization systems  10  and  11  are preferably supplemented by temporary locking systems that are separate from or incorporated within these immobilization systems such as, for example, rotating or latch-based locks—notably the twistlock type used for securing ISO containers. 
     Any other appropriate means of temporary immobilization of the hitch attachment  9  on the accommodating platform  8  of the wagon  1  can be considered. 
     Assembled on the chassis  2  of each basic wagon  4 , there is a pivoting turntable  14 . This pivoting turntable  14  allows the corresponding accommodating platform  8  to accommodate and bear a road-hauled semi-trailer  15 , of which the system according to the invention allows loading, transportation and unloading. 
     The system according to the invention is universal; it is suitable for any type of semi-trailer  15  regardless of its type, model and length, provided that it has a kingpin  16  at the front and a wheel assembly  17  at the back—with three axles, for example. 
     The pivoting turntables  14  are each assembled so as to pivot freely or driven by a motor on the chassis  2 , by suitable systems involving, for instance, a central pivoting pin with, possibly, the assistance of bearing rollers on a crown, jockey wheels, roller bearings or any other equivalent system that is of commonplace technology and that, consequently, will not be described herein. 
     The pivoting turntables  14  can be oriented by pivoting—preferably manually or possibly motor-driven—between two characteristic positions: one transportation position ( FIG. 2 ) in which they are aligned along the longitudinal axis of the wagon, and a loading or unloading position ( FIG. 4 ) in which they are perpendicular to the longitudinal axis of the wagon or obliquely positioned in relation to it. 
     The pivoting turntables  14  are preferably immobilized in these two characteristic positions by any suitable locking system—for example, mechanical, pneumatic or hydraulic—preferably manually. 
     The pivoting turntables  14  are preferably considerably shorter than the chassis  2  on which they are assembled, this length preferably being slightly greater than that of the wheel assembly  17  of the semi-trailers  15 . 
     In the transportation position, the pivoting turntables  14  do not support the entire corresponding semi-trailer, only its rear portion by means of its wheel assembly  17 , the front part of the semi-trailer  15  being supported by the accommodating platform  8  via the kingpin  16 , which is immobilized within the hitch attachment  9 . 
     One feature of the system according to the invention is that the accommodating platform  8  is connected to the chassis, and is independent of the pivoting turntable  14 . Thus, the semi-trailer  15  is directly locked to the chassis  2  of the wagon  1 , via its kingpin  16 . In addition, the pivoting of the pivoting turntable  14  is also locked by this arrangement. 
     The pivoting turntable  14  may incorporate, at one of its ends, an access ramp such as  18 , consisting—for example—of a retractable end plate assembled with elastic return to the upper position, as illustrated in the figures. This access ramp  18  ensures a continuous transition between the rolling surface constituted by the trackside loading platform  19  and the turntable  14  accommodating the wheels of the semi-trailer  15 . 
     In the event that there are two trackside loading/unloading platforms  19  on either side of the railway track on which the semi-trailer  15  transportation wagon  1  is located, the pivoting turntable  14  may be required to cross over to the road haulage tractor of the semi-trailer  15 , and transferred from one trackside platform to the other, so as to be able to load the semi-trailer  15  in forward travel on to the pivoting turntable  14 . 
     In this case, the pivoting turntable  14  will preferably be equipped with two access ramps  18 —with one at each of its extremities—so as to provide a continuous transition with each of the trackside loading platforms  19  on each side of the railway line. 
     As a variant, this retractable access ramp  18  can be replaced by an end extension—an articulated or telescopic appliance, for example—or simply by the extremity of the pivoting turntable  14 . This extension can swing so as to have a raised or retracted resting position. 
     This extension is intended to obtain the same level between the rolling surface of the trackside loading platform  19  and the bearing surface of the corresponding pivoting turntable  14 ; the transversal edge  20  of the extremity of the turntable  14  or its extension should be—in the turntables loading/unloading position —sufficiently close to the edge of the trackside platform for the gap existing between the two to be easily crossable by the semi-trailer  15 . 
     To facilitate the pivoting of the pivoting turntable  14  when this extremity or end extension is fixed, it is possible to, for example, incorporate a localised curved concave hollow within the structure of the trackside loading platform  19 , opposite this extremity, and a curved convex extremity in the turntable  14 , so as to allow clearance at the corners during the pivoting of the pivoting turntable  14  in order to change between one or other of its characteristic positions. 
     It is also possible to use pivoting turntables  14  with oblique transversal edges, such as in the variant illustrated in  FIGS. 35 to 38 . Obviously, this implementation is preferable to the preceding arrangement, because it does not involve modifying the structure of the trackside loading platforms  19 . 
     The pivoting turntables  14  preferably incorporate a set of four shims  21 —with two rear shims  22  and two forward shims  23 —that immobilize the end wheels of the semi-trailer&#39;s  15  wheel assembly  17  when it has been loaded on to the pivoting turntable  14 . 
     In the event that the pivoting turntable  14  is only accessible by one of its transversal edges  20 , which requires loading the semi-trailer  15  in reverse, the rear shims  22  can be fixed in relation to the turntable  14 . They can be assembled in a fixed manner on to the pivoting turntable  14 , or can be directly integral to it. However, the forward shims  23  must be moveable or detachable, so as to provide clear passageway on the pivoting turntable  14  during the phases of loading and unloading of the semi-trailer  15 , as will be seen subsequently. 
     In the event that the pivoting turntable  14  is accessible by each of its transversal edges  20 , thereby making it possible to cross the turntable and load the semi-trailer  15  in forward, all the shims  21 —namely the rear shims  22  and the front shims  23 —are moveable or detachable so as to leave the pivoting turntable  14  completely free for the phases of loading and unloading of the semi-trailer  15 . 
     Of course, any other suitable means of immobilizing the wheel assembly  17  of the semi-trailer  15  can be considered. 
     A solution without shims can also be considered; in this case, the semi-trailer  15  is immobilized only by its kingpin  16 . The turntables  14  then preferably have lateral edges enabling proper centering of the semi-trailer  15 . These edges are also used to restrain the semi-trailer  15  when lateral stresses are exerted during rail transportation. 
     In another more sophisticated version, the locking of the semi-trailer&#39;s  15  wheel assembly  17  can be done automatically—for example, when the pivoting turntable  14  is immobilized in the transportation position. 
     One of the important features of the semi-trailer rail transportation system according to the present invention is the hitch attachment  9 . It is shown in more detail in  FIGS. 5 to 7 . 
     It is a bearing support that provides support for the front of the semi-trailer  15  during the loading and unloading phases, with the assistance of a machine—notably a moving handling appliance  24 , such as a forklift truck  25  with forks for gripping  26  —but also during rail transportation when it is placed on the accommodating platform  8  connected to the chassis  2  of the wagon  1 . 
     As such, this hitch attachment  9  constitutes the interface, firstly between the semi-trailer  15  and the handling machine  24  during the loading and unloading phases and, secondly, between the semi-trailer  15  and the wagon  1  during rail transportation. 
     It generally consists of a body  27 , which is assembled in a detachable manner on the accommodating platform  8  of the wagon  1 , and, preferably, a hitch  28  designed to accommodate and immobilize the kingpin  16  of the semi-trailer  15 , with any other system of locking of the kingpin  16  of the semi-trailer  15  also being possible. 
     The body  27  takes the form of a mechanical base composed, for example, of a frame structure or of exterior and interior longitudinal  29  and transversal  30  plates. 
     The body  27  is advantageously grippable by a handling machine  24 . For this, it has a mechanical interface system  31  compatible with the gripping system of this machine. In the illustrated variant, it is, for example, a series of apertures  32  arranged in alignment within the longitudinal  29  and/or transversal  30  plates of the body  27 , so as to leave the interior space free for the insertion of the fork(s)  26  of the forklift truck  25 . 
     Depending on the variant and the layout of these openings  32 , the apertures can be transversal or longitudinal or both at the same time, as can be seen in the example in  FIG. 5 . In the latter case, the forklift truck  25  can advantageously take up the hitch attachment  9  via any of its faces, and employ it, according to wishes, for transversal or longitudinal presentation. 
     However, other handling machines  24  can be used, such as a port crane or other lifting appliance of crane or beam type, for example. The mechanical interface system  31  can be different, according to the type of handling machinery used. For a crane, for example, the openings  32  providing apertures for the arms of the fork  26  of the forklift truck  25  can be replaced, for example, by attachment rings for slings. Different mechanical interface systems  31  can advantageously coexist on the body  27  of the hitch attachment  9 , to make it compatible with various types of handling plant. 
     As previously mentioned, the body  27  of the hitch attachment  9  also comprises an immobilization system  11  complementary to the system  10  on the accommodating platform  8  of the wagon. 
     In the variant illustrated, the complementary immobilization system  11  is composed of perforated section bars  33 , along the longitudinal edges or longitudinal plates  29  of the body  27 , with each having a series of openings  13 —square, for example—that fit into each other or that are entered by the pins or lugs  12 —four, for example—existing on the accommodating platform  8  connected to the chassis  2  of the wagon  1 . 
     The multitude of openings  13  present on the perforated section bars  33  compensate for the differences of distance that might exist, depending on the model of semi-trailer, between the kingpin  16  and the wheel assembly  17  of the semi-trailer  15 . Regardless of the distance and, therefore, regardless of the position of the hitch attachment  9  assembled on the kingpin  16  of the semi-trailer  15 , there are openings  13  that are substantially in opposition and that can be entered by the lugs  12  of the accommodating platform  8  when the pivoting turntable  14  is in the transportation position. As such, the assembly of the hitch attachment  9  on to the wagon&#39;s accommodating platform  8  is always possible. 
     These perforated section bars  33  could also be provided along the transversal edges or transversal plates  30  of the body  27 , so as to make it possible, in a symmetrical configuration of the body  27 , to assemble the hitch attachment  9  on the wagon&#39;s accommodating platform  8 , regardless of the direction of presentation of the hitch attachment  9  by the handling machine  24 . 
     On the body  27  of the hitch attachment  9  and, preferably, substantially in its center, a shaft  34  is assembled, telescopically extended by an end section  35  on the free extremity, on which the hitch wheel  28  is assembled pivotally. The pivoting of the hitch  28  is limited to pivoting around a horizontal axis, namely parallel to the base plane of the body  27  of the hitch attachment, and perpendicular to the direction of travel. Thus, the hitch is free in pitch but impeded in roll. In this way, the semi-trailer  15  is maintained with regard to roll when positioned on the wagon  1 . 
     The technical form of the hitch  28  is intended to be compatible with the kingpin  16  of the semi-trailers  15  to be loaded, and it is generally a standardized hitch  28 . This hitch  28  is equivalent to those existing on the road haulage tractors  36  to which the semi-trailers  15  to be transported are coupled. 
     It comprises a convergent entry  37 , a slot  38  for the kingpin  16 , and a locking system for the said kingpin that can be released via actuating handle  39 . 
     Locking the kingpin  16  into the hitch  28  is conventionally accomplished by longitudinal engagement of the hitch  28  around the kingpin  16 , until it is located in the slot  38 , this engagement being facilitated by the convergent form of the entry  37 . The locking of the kingpin  16  is then automatic. When the kingpin  16  is locked into the hitch  28 , all its movements in relation to the hitch  28  in the three directions are blocked. Therefore, the orientation of the hitch  28 , as seen from above, is unimportant. 
     The hitch  28  is preferably assembled so as to be adjustable heightwise in relation to the body  27  of the hitch attachment  9 . For this, the end section  35  is assembled so as to slide telescopically within the shaft  34 , to allow heightwise adjustment of the hitch  28  in relation to the body  27 . Immobilization in a given position is achieved by any suitable means: clamping, pinning as illustrated, or whatever other system. 
     This height adjustment mechanism can be designed to be operated by an operator, or by a change in the height of the fork  26  of the forklift truck  25 , or any other equivalent facility of the handling machine  24  used. 
     Other systems of heightwise adjustment are also possible—at the accommodating platform  8 , for example. 
     In one basic version, insofar as the gauge allows or if, for example, the height of the kingpins  16  of the semi-trailers  15  is constant, this height adjustment feature can be eliminated. 
     This mechanism is automatically locked to take up all the vertical forces caused by the semi-trailer  15 . As such, the kingpin  16  held by the hitch  28  is immobilized in all directions. 
     To ensure a damping function with respect to longitudinal shocks that can occur during rail transportation, and also to provide the deflection necessary to absorb the adjustments due to the positioning of the semi-trailer  15  on the wagon  1 , the shaft  34  is preferably mechanically secured on to the body  27  by means of an oblique arcing  40 —for example, implemented by a cylinder, a spring or any similar means, with mechanical elastic return or other means of return of the shaft  34  supporting the hitch  28  towards the center, namely to an straight vertical position. 
     A basic version without the capability of longitudinal deflection of the hitch  28  is also possible, especially in the event that the wheel assembly  17  of the semi-trailer  15  is not bearing against shims  21 . 
     Obviously, other forms of hitch attachment  9  are possible. The advantage is that they should be grippable by a handling machine  24 , particularly a machine with forks  26 . The appliance taken as an example henceforth in this description is a mobile machine of forklift truck type  25 , having a fork-based gripping device  26  assembled on one of its extremities, which is known for the handling and manipulation of pallets and containers. 
     Elaborating on the same inventive principle, one could envision employing pivoting turntables  14  with oblique transversal edges  20 , so that one can load and unload semi-trailers  15  on either side, from two trackside loading and unloading platforms separated by the railway track on which the wagon  1  for transportation of the semi-trailers is positioned, preferably using the road haulage tractor  36  of the semi-trailer  15  to be loaded. 
     This possibility is illustrated in  FIGS. 35 to 38 . 
     These oblique transversal edges  20  allow one to pivot the turntable  14  in the direction of clearance of the corner furthest from the adjacent edge of the trackside platform  19 , without it coming into contact with this edge. This element facilitates oblique loading with transition of the road haulage tractor  36  of the semi-trailer  15  on to the pivoting turntable, above the railway track, from one trackside platform to the other, as can be seen in  FIGS. 36 and 37 . 
     In all cases, when the semi-trailer is loaded on the wagon  1  in rail transportation position, it rests on its wheel assembly  17 , preferably restrained laterally by the lateral edges  41  of the pivoting turntable  14 , bearing against the hitch  28  via its kingpin  16 . Vertical, longitudinal and lateral movement of the kingpin  16  is restrained by the hitch  28 , which is itself immobilized on the chassis  2  by means of the accommodating platform  8 —for example, by means of lugs  12 . An additional immobilization can be applied if the semi-trailer  15  is chocked at its wheel assembly  17  by shims  21 . 
     A description of the positioning of a semi-trailer  15  on a dual wagon  1  now follows, supported by the accompanying  FIGS. 8 to 34  in the scope of the transportation system according to the invention. 
     This load positioning can be done either by using the road haulage tractor  36  of the semi-trailer  15  to place it on the pivoting turntable  14  from a trackside platform  19 , or by immediate use of the forklift truck  25  and the hitch attachment  9 , working from the same trackside platform  19 . 
     These two possibilities are considered in the description below. 
     Firstly, the initial loading phase is examined, which is carried out using the road haulage tractor  36  of the semi-trailer  15 . This method, which is illustrated in  FIGS. 8 to 17 , is preferred. However, it requires the presence of the wagon  1 . If the intention is to prepare the loading of the wagon  1 , the second solution illustrated in  FIGS. 18 to 32  will be preferable. 
     The semi-trailer  15  is moved, by means of its road haulage tractor  36 , on to the trackside loading platform  19 , in reverse position, opposite the pivoting turntable  14 , which has been pivoted so that it is in loading position, perpendicular to the longitudinal axis of the wagon and the platform edge ( FIGS. 8 and 9 ), or is oriented obliquely at an angle chosen by the operator—to optimize the footprint, for example. The access ramp  18  preferably provides the connection between the trackside loading platform  19  and the corresponding pivoting turntable  14 . In this position, the pivoting turntable  14  is immobilized in relation to the chassis  2  of the wagon  1 . 
     The road haulage tractor  36  pushes the semi-trailer  15  in reverse as far as its final position on the pivoting turntable  14 . In this position, the wheel assembly  17  of the semi-trailer  15  notably occupies the entire length of the pivoting turntable  14 , and the rear wheels of the wheel assembly are immobilized by the fixed rear shims  22 . The forward shims  23  are then positioned so as to immobilize the front wheels of the wheel assembly  17  ( FIGS. 10 and 11 ). 
     The road haulage tractor  36  then leaves the semi-trailer  15  in this position, after releasing the legs  42  ( FIG. 13 ), and deflates the semi-trailer&#39;s  15  pneumatic suspension, The electrical and pneumatic connections between the road haulage tractor  36  and the semi-trailer  15  are also disconnected. As such, the semi-trailer  15  is automatically braked. 
     If there is a pivoting turntable  14  that crosses in relation to the two opposing edges of two trackside platforms  19 , one can envision using the semi-trailer&#39;s road haulage tractor  36  in forward travel, so as to position it on the pivoting turntable  14 . 
     In the above cases, the advantage of conserving the pneumatic and electrical connection between the road haulage tractor  36  and the semi-trailer  15 , until the entry of the semi-trailer  15  on to the pivoting turntable  14  is maintained. For loading by forklift truck  25  (second loading method described below), the hoses have to be reconnected to the forklift truck  25 , in order to release the brakes of the semi-trailer so that one can move it. One of the advantages of this first method is that one only has to perform these operations once. 
     The forklift truck  25  with forks  26  and the hitch attachment  9  are then employed. After adjusting—if necessary—the height of the hitch  28  ( FIG. 12 ) in relation to the placement surface of the semi-trailer  15  on to the wagon  1 , so that the semi-trailer  15  is perfectly horizontal in rail transportation position, the forklift truck  25  assembles the hitch  28  on the kingpin  16  of the semi-trailer  15  ( FIG. 14 ). It is also possible to adjust the height of the hitch  28  by means of the fork(s)  26  of the forklift truck  25 , after placement of the hitch attachment  9  on the kingpin  16 . 
     The forklift truck  25  then pushes the hitch attachment  9 , pivoting it 90°, so as to pivot the pivoting turntable  14  and place it in the transportation position, aligned within the longitudinal axis of the wagon  1  ( FIGS. 15 and 16 ). 
     To achieve this, the front of the semi-trailer  15  is raised slightly to release the legs  42 , and then lowered when the hitch attachment  9  arrives above the corresponding accommodating platform  8  ( FIG. 17 ). 
     Loading with only the forklift truck  25 —which is the second method of loading—is illustrated in  FIGS. 18 to 32 . 
     As previously, the hitch  28  is adjusted in height, if necessary, in relation to the body  27  of the hitch attachment  9 , to ensure the horizontality of the semi-trailer  15  in the rail transportation position—this adjustment can be done before or after locking the hitch  28  on to the kingpin  16 . 
     The forklift truck  25  takes hold of the hitch attachment  9  by means of its fork  26 , and approaches the semi-trailer  15 , so as to present and then connect the hitch to the kingpin  16  ( FIGS. 19 to 22 ). 
     After pneumatically and—if necessary—electrically connecting the forklift truck to the semi-trailer  15  to release its brakes, the forklift truck  25  lifts the front of the semi-trailer  15  so as to retract the legs  42 , and pushes it backwards on to the pivoting turntable  14  ( FIGS. 23 to 26 ), until it comes into contact with the rear fixed shims  22 . One then positions the detachable forward shims  23 , and then the forklift truck  25  performs a rearward movement to cause the semi-trailer  15  and the pivoting turntable  14  to pivot into the longitudinal axis of the wagon  1  ( FIGS. 27 and 28 ). This manoeuvre involves a path following the dotted line and the arrow illustrated in  FIG. 27 . 
     A variant manoeuvre is shown in  FIGS. 29 and 30 . This involves a disengagement of the forks  26  of the forklift truck  25 , and their subsequent re-engagement in a different position, offset by 90° in relation to the body  27  of the hitch attachment  9  ( FIGS. 29 and 30 ). After placement of the hitch  28  and the positioning of the semi-trailer  15  on the pivoting turntable  14  by means of a rearward movement of the forklift truck  25  as above, the forklift truck  25  is moved into a pushing position in which it is perpendicular to the front of the semi-trailer  15 . From this position, the forklift truck  25  pivots the semi-trailer  15  by 90°, until it is aligned with the longitudinal axis of the wagon  1 , following a path illustrated in  FIG. 29  by two dotted lines. 
     The hitch attachment  9  is then lowered on to the accommodating platform  8 , centering it, so that the immobilizing pins or lugs  12  pass through the openings  13  of the body  27 . The height of the hitch  28  will have been adjusted previously, if necessary, so that the semi-trailer  15  is properly horizontal when it is in the immobilized transportation position ( FIGS. 31 and 32 ). 
     The unloading phases are similar to the loading phases described above, but in reverse order. 
       FIGS. 33 and 34  show two semi-trailers  15  in position on a dual rail wagon. 
     Note the perfectly horizontal positions and the universal nature of the loading and transportation system, which can be adapted for very many types of semi-trailers 
     During the loading of semi-trailers  15  in accordance with the variant illustrated in  FIGS. 35 to 38 , the road haulage tractor  36  of each semi-trailer  15  positions it on the corresponding pivoting turntable  14 , which is in the loading position—for instance, oblique in relation to the longitudinal axis of the wagon  1 . To do this, the road haulage tractor  36  coupled to the semi-trailer  15  crosses the railway line between the two opposing trackside platforms  19 , using the corresponding pivoting turntable as a crossing bridge. 
     The phases of immobilization of the wheel assembly  17  of the semi-trailer  15 , by means of shims  21 , of placement of the hitch  28  by means of the hitch attachment  9 , and of pivoting of the pivoting turntable  14  are the same as for the basic version. Obviously, the pivoting turntables  14  can be motor-powered. In this case, the forklift truck  25  simply follows the movement. 
     In a sophisticated version, the locking of the wheels can be done automatically—for example, when one lowers the turntable  14  on the wagon  1 . 
     A description has only been provided for a dual wagon above; obviously, a single wagon  1  falls within the scope of the invention and, to be profitable, the transportation system should preferably include a multitude of wagons that together form a railway train. 
     Obviously, the invention is not limited to the preferred embodiments described above and illustrated in the various figures. Many other variants are possible while remaining within the same inventive principle defined by the claims.