AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INVENTION TITLE: TRANSPORTATION DEVICE FOR CABLEWAY SYSTEMS The following statement is a full description of this invention, including the best method of performing it known to us:- TRANSPORTATION DEVICE FOR CABLEWAY SYSTEMS CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority, under 35 U.S.C. § 119, of Austrian patent application A 1964/2007, filed December 3, 2007; the prior application is herewith incorporated by reference in its entirety. BACKGROUND OF THE INVENTION [0002] Field of the Invention: [0003] The present invention relates to a transportation device, mainly a gondola or a chair formed with a covering hood, for a cableway system having a supporting and conveying cable which is guided, in the stations, over deflecting pulleys, of which at least one is driven. The transportation device is firmly clamped to the supporting and conveying cable or it can be coupled thereto and, in the stations, can be uncoupled therefrom and moved along guide rails, through the boarding and disembarking regions, at a speed which is considerably reduced in relation to the speed of the supporting and conveying cable, and the passengers board the transportation device or disembark therefrom in the process. The gondola is formed with transparent wall parts or the chair is formed with a transparent covering hood mounted in a pivotable manner thereon. [0004] Prior art cablecars are formed predominantly with wall parts made of a transparent plastic material. It is likewise the case that the covering hoods for chairs of cableway systems are produced from a transparent plastic material. The advantage of forming cablecars with a very large number of transparent wall parts, or of forming covering hoods which are transparent, resides in the particular level of convenience for the users of the cars or of the chairs, who are thus afforded a largely unrestricted view of the landscape. [0005] The transparent wall parts for cars, or covering hoods, which consist of a plastic material e.g. of polycarbonate, are produced by panels of the plastic material being pressed in heated molds, this achieving the desired three-dimensional configurations. -2- [0006] Wall parts for cablecars and covering hoods for chairs need to have largely constant wall thicknesses of approximately 3 mm to 5 mm in order thus to ensure the necessary strength. Production of these wall parts and of the covering hoods, however, gives rise to the problem where, on account of the resistances during the deformation of the plastic material which are brought about by the different three-dimensional configurations, it is possible for regions which have insufficient low wall thicknesses to form. This applies, in particular, to corner regions. If these shortcomings are not detected, these products are processed further, i.e. they are used in cars and in chairs in which case the insufficient strength results, within short periods of operation, in damage, in particular fracturing, which makes it necessary for the relevant wall parts or covering hoods to be replaced by new wall parts or covering hoods. SUMMARY OF THE INVENTION [0007] It is accordingly an object of the invention to provide a transportation device for a cableway system which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which allow these production-related shortcomings of the wall parts or of a covering hood to be immediately detected, as a result of which these can be separated out straightaway. [0008] With the foregoing and other objects in view there is provided, in accordance with the invention, a transportation device for a cableway system having a supporting and conveying cable extending between stations and guided about deflecting pulleys, wherein at least one of the pulleys is a driven pulley and the transportation device is firmly clamped to the supporting and conveying cable or configured to be coupled thereto and uncoupled therefrom in the stations, for movement along guide rails extending through boarding regions and disembarking regions at a speed substantially below a speed of the supporting and conveying cable, for enabling one or more passengers to board the transportation device or disembark therefrom in the station. The transportation device is formed with one or more transparent wall parts or it has a transparent covering hood pivotally mounted thereon. The improvement according to the invention is found in the fact that the one or more transparent wall parts or the transparent covering hood is/are produced from a plastic material containing at least one dye. -3- [0009] In other words, the objects of the invention are achieved in that the wall parts or the covering hood are or is produced from a plastic material containing at least one dye. [0010] As a result of the dye contained in the plastic material, regions of a large wall thickness have more pronounced coloring, whereas regions with a small wall thickness have lesser coloring. This makes it possible to detect straightaway whether the relevant product meets the technical requirements in respect of the necessary wall thickness or whether it is unsuitable for further processing and has to be separated out. [0011] Plastic materials to which at least one dye is added also achieve the effect where particles of infrared radiation are stored in the dye particles, as a result of which the wall parts or the covering hood are or is heated to a more pronounced extent than is the case with plastic materials which are not dyed. This means that the wall parts of cablecars and the covering hoods of chairs ice up to a lesser extent and the surfaces dry more quickly. In addition, the transparent wall parts or covering hoods which are tinted as a result of being dyed provide antidazzle protection for the passengers in strong sunshine. [0012] In accordance with a concomitant feature of the invention, the wall parts or the covering hood (3) are or is produced from panels made of a plastic material, containing at least one dye, by way of a pressing operation which takes place in heated molds. (0013] The instant application contains certain overlapping subject matter, such as information concerning the molding and inspection process, with my copending patent application No. [Attorney Docket WRA-36066], which is herewith incorporated by reference. [0014] Other features which are considered as characteristic for the invention are set forth in the appended claims. [0015] Although the invention is illustrated and described herein as embodied in transportation device for cableway systems, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. -4- [0016] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING [0017] Fig. 1 is a perspective view of a lift chair of a cableway-system with a covering hood, which is illustrated in an open position; and [0018] Fig. 2 is a similar perspective view of the chair according to Fig. 1, this time with the covering hood in the closed position. DETAILED DESCRIPTION OF THE INVENTION [0019] Referring now to the figures of the drawing in detail, the cableway-system chair which is illustrated as an exemplary embodiment of the invention comprises a carrying frame 1 which has a seat surface 2 for a number of passengers. In order to provide the passengers protection, for instance from inclement weather, a covering hood 3, also referred to as a bubble, is mounted on the carrying frame 1. The hood 3 is pivotally mounted about an axis 31. In the open position of the covering hood 3 - the position illustrated in Fig. 1 - passengers can be seated and they can disembark from the chair. If the passengers require protection against wind, snowfall or other climatic effects as they are traveling on a cableway system, the covering hood 3 is pivoted into the closed position - the position illustrated in Fig. 2. [0020] The covering hood 3 is produced fully, or for the most part, from a plastic material, in particular from polycarbonate, to which at least one dye is added. The addition of a dye thus makes it possible to detect, following production of the covering hood, whether the latter has the wall thickness of approximately 3 mm to 5 mm which is necessary for the desired strength, since regions with a small wall thickness have a lighter tinting than regions with a greater wall thickness. [0021] If it is established that a covering hood has one or more regions with an insufficient wall thickness, and thus obviously does not ensure the necessary strength, this covering hood is separated out. Since this, to the greatest extent possible, rules out production-related damage, in particular fracturing, changeover operations which would otherwise be necessary are avoided, and substantial savings in cost are achieved as a result. [0022] Producing covering hoods from a plastic material which contains a dye, furthermore, results in the covering hood being heated up more quickly and being de-iced more quickly. In addition, such a covering hood provides a certain amount of shade and antidazzle protection for the users of the chair. [0023] It will be readily understood that such covering hoods can be used both for chairs which are rigidly fastened on the carrying and conveying cable of a cableway system and for chairs which can be coupled to the carrying and conveying cable. [0024] The same advantages as outlined also apply to cableway-system cars and gondolas that are formed with transparent wall parts.