Title: "CASTING PROCESS OF A TRUCK SIDEFRAME, CASTING MODEL, RAILWAY CAR TRUCK SIDEFRAME, RAILWAY CAR TRUCK AND RAILWAY CAR"
Field of the Invention The present invention refers to a casting process for a railway truck sideframe and a casting model for the aforesaid casting process. By the elimination of the cores of the central section and the bases, and the cavity formation elements designed to position them into the model, benefits are produced in comparison to the already existing processes. Description of the Prior Art
The railway car truck is designed to support the axles, wheels and suspension of the car, absorbing the impacts resulting from the forces that occur during its movement along the railways. A typical truck has an area of direct contact with the lower external surface of the car through a central bolster, with each one of its extremities resting on spring assemblies. These spring assemblies are located in a section of the truck known as the sideframe. This is one of the most important structural sections because, as well as containing the spring assemblies or other elastic elements, it also houses the extremities of the car wheel axles. Normally, this sideframe is made of metal and manufactured by a casting process that, despite numerous variations in its stages, contains the following basic stages, which are well known in the prior art. Therefore, only a few general comments are required. These will be explored further in the detailed description, when the stages will be described in a manner relevant to the object of the present invention:
(i) Manufacture of the casting model;
In this stage, a model with the approximate format of the part to be cast is constructed. It is designed to forecast the contraction of the material, due to the cooling of the metal after the pouring of the casting metal. (ii) Manufacture of the mold;
After the manufacture of the casting model, the model is placed in a mold container. A refractive material, normally composed of sand and ag-
glomerate, is molded over the model which, after the removal of the mold container, leaves a cavity with a complementary or negative format of the part to be cast.
(iii) Manufacture of the cores; The cores are devices made of sand. They are designed to provide internal spaces, walls, cavities, holes and access points in the part.
(iv) Placement of the cores into the mold;
After their manufacture, the cores should be placed over the mold so that, with the pouring of the casting material (next stage), cavities are produ- ced in the final part.
(v) Pouring of the casting material;
At this point, the casting material, normally a metallic alloy, is poured so that the mold containing or not containing the cores is filled.
(vi) Removing the mold After a determined period of time, for the part to cool down and solidify within the mold, the part is then removed either manually or by a mechanical process.
After the part has been removed from the mold, it is necessary to re- move any burrs that have formed during the casting process and to clear any resulting incrustations of sand used in the manufacture of the mold. It is also possible, during this stage, to perform specific thermal treatments on the constituent metal of the part obtained by this process.
Generally, the model is divided into two halves (bipartite) to form two molds, one for each half, which are placed face to face. When they are connected together, they produce the entire cavity made by the insertion of the part into the mold container. The casting material is then poured through the channels that guide the casting material into the mold cavity, in order to fill and produce the final part. With respect to the casting processes specific to railway car truck si- deframes, the prior art has certain examples, such as patent document Pl 9403781-7. This describes the format configuration of a truck sideframe, re-
suiting in a weight reduction of the sideframe structure, by the more efficient use of the geometry of the part and the materials. The maximization of this construction is supplied by the form given to the whole of the sideframe structure, such as the solid form of the unitary transversal section of the "I" beam. The document also states that the new "I" beam configuration allows easier inspection and therefore improves the quality of the mold, due to a substantial reduction in the use of cores for the casting.
The process described in this document, despite appearing beneficial, requires a complete overhaul in the manufacture of the molds and the cores used to obtain the truck sideframe. This requires a high investment to alter or adapt the process in order to implement the casting proposed in this document.
Moreover, because in most of the casting processes for railway truck sideframes the cores are positioned over the mold by a simple attachment, there are countless disadvantages and problems that can be found in the part after the casting. One example of these problems is where one or more cores shift when the casting material is poured through the mold, forming burrs, or causing faults when, for example, the sand of the de-agglomerated core enters into contact with the casting material and the sand particles re- main incorporated in the poured part and contaminate it.
Another example of prior art can be found in patent document US 6,662,853, which describes a method of construction of a railway car truck sideframe by the division of the sideframe in parts, using core modules to form the internal surfaces of the sideframe. The core modules are located in the following areas: the left extremity, the right extremity, the left tension are- a, the right tension area, and the central area.
This document joins together several cores in blocks of cores, so that for this solution to be employed it is necessary, once again, to perform expensive alterations in the production stage of the cores, which can increase the cost of the process.
Therefore, it can be seen that there has still not been developed a casting process, and/or even a casting model, which effectively reduces the
number of cores, without drastically altering the process or the structure of the involved stages, and without requiring a very large overhaul to alter the standards of the casting processes for the railway truck sideframes. Also, there is no casting process and/or casting model, which provides not only simplicity but also a substantial improvement in the finishing of the truck side- frame, eliminating a large part of the work employed in this stage. Objectives of the Invention
Therefore, it is the primary objective of this invention to provide a casting process that effectively reduces the number of cores in order to obtain a railway truck sideframe with less faults, less burrs, less inclusions, a substantial reduction in the finishing work, an improved dimensional stability, a low incidence of core/metal sand, and a better surface appearance.
Furthermore, a second objective of this invention is to produce a casting model to be used in a casting process, to provide the same advantages described in the previous paragraph.
Finally, a third objective of this invention is to provide a truck sideframe for railway cars, which has the best surface finishing and is manufactured by the casting process described in the first objective of this invention. A Brief Description of the Invention The first objective of this invention is achieved by means of a casting process of a truck sideframe, involving the following stages:
(i) Manufacture of the model, comprising the construction of a casting model in a format substantially analogous to a truck sideframe, to forecast the contraction of the material after the pouring of the metallic alloy; (ii) Manufacture of the mold, comprising the insertion of the casting model into a mold container and the subsequent removal of this casting model from the aforementioned mold container, after being filled with molding sand and compacted;
(iii) Manufacture of the cores of the truck sideframe, comprising the fa- brication of the cores: of the first and second sideframe sections of the casting model; of the first and second areas of connection between the first and second sideframe sections of the casting model; and the section adjacent to
(iv) Placement of the cores into the mold, comprising the positioning of the cores fabricated in stage (iii) over the mold, as follows: the core of the superior and lower central section is positioned between the cores of the si- deframe sections, and the core adjacent to the base is also positioned;
(v) Pouring of the casting material, comprising the filling of the mold containing the cores placed in stage (iv) with the casting material.
(vi) Removing the mold, comprising the removal of the poured, cooled and solidified part by the pouring of the casting material in stage (v); and (vii) Finishing, comprising the treatment of the surface of the truck si- deframe obtained by stages (i) to (vi).
This process also comprises the characteristic of eliminating, in stage (iv), the cores of the bases and the central section of the truck sideframe.
The second objective of this invention is achieved by means of a cas- ting model, using the casting process briefly described above, comprising a first sideframe section connected by a central section to a second sideframe section.
The sideframe sections are symmetrical, parallel, and diametrically opposite each other, each one of them comprising of a supporting arm, adja- cently connected to an elongated bolster. The supporting arm extends obliquely from the area of contact between the sideframe section and the central section in the direction of the elongated bolster. The elongated bolster also extends from the area of contact between the sideframe section and the central section and has a free extremity, which comprises a first tooth of the ba- se. The supporting arm also comprises, in the area of connection with the elongated bolster, a second tooth of the connected base. This second tooth of the base is spaced and substantially parallel in relation to the first tooth of the base. The space between the first and second base arms is filled with a base cavity formation element. On the other hand, the central section comprises a first element of connection associated in a contiguous manner with the elongated bolsters of the first and second sideframe sections, and a second element of connection
associated in a contiguous manner with the supporting arms of the first and second sideframe sections. The first and second elements of connection are substantially parallel and spaced between themselves. The space between the first and second connection elements is filled with a central cavity forma- tion element.
This casting model also comprises the characteristic of having the cavity formation elements for the housing of the cores in the eliminated bases and central section.
The third objective of this invention is achieved by the production of a railway car truck sideframe, which has the principal characteristic of being produced in accordance with the casting process of the present invention. A Brief Description of the Designs
The present invention will now be described in more detail, based on the examples represented in the designs. The figures represent the following: Figure 1 - Flowchart illustrating the stages of the casting process of the present invention;
Figure 2 - Perspective view of one half of the model of the bipartite casting;
Figure 3A - Overhead view of the cores of the first and second sideframe sections of the casting model;
Figure 3B - Overhead view of the core of the first area of connection between the first and second sideframe sections of the casting model;
Figure 3C - Overhead view of the cores positioned over the second area of connection between the first and second sideframe sections of the casting model;
Figure 3D - Overhead view of the core adjacent to the base;
Figure 3E - Overhead view of the core of the brake system guide;
Figure 3F - Overhead view of the auxiliary core of the lower back area;
Figure 4 - Overhead view of one half of the casting mold; and Figure 5 - Overhead view of one half of the casting mold with the cores in position. Detailed Description of the Figures
1 ) Casting Process
Initially, it is important to note that the casting process of the present invention comprises the same stages as the prior art processes which, as will be demonstrated, is advantageous. This is because it is not necessary to alter the principal characteristics of the process to obtain the benefits brought by the process of the present invention.
The stages of the process are illustrated in figure 1 , as follows. (i) Manufacture of the model
This stage comprises the fabrication of a casting model 1 in a format that defines the format of a truck sideframe, to forecast the contraction of the material after the pouring of the molten alloy. This casting model can be made of any material such as wood, polymer or preferably metal, or a combination of these materials. It is worth emphasizing that that the casting model 1 , in any of its possible forms, has dimensions slightly larger than the truck side- frame when it is finished, due to the contraction of the metal that fills the mold, feeding the heat and forming the part.
The casting model 1 of the present invention is bipartite, comprised of two halves, each corresponding to one half of the truck sideframe. However, this fact does not limit the scope of protection for the present invention. The casting model 1 of the present invention, as illustrated in figure 2, comprises basically a first sideframe section 10 connected by a central section 11 to a second sideframe section 12. Both these sideframe sections 10 and 12 are symmetrical, parallel and diametrically opposite to each other. The central section, in turn, comprises: a first element of connection 19 asso- ciated in a contiguous manner to the first 10 and second 12 sideframe sections; and a second element of connection 20 also associated in a contiguous manner to the first and second sideframe sections 10 and 12. The first 19 and second 20 elements of connection are substantially parallel and spaced between themselves. Each one of the sideframe sections 10 and 12 is for- med of smaller parts, which will be described later.
Furthermore, the casting model 1 of the present invention comprises, in the extremities of the first 10 and second 12 sideframe sections, a base
30, which has the function of protecting the ends of the truck sideframe wheel axles, after the conclusion of the casting process.
The casting model 1 will be described in more detail later because further information about its structure is not relevant here. (ii) - Manufacture of the mold
After the fabrication of the casting mold 1 , it is necessary to manufacture the mold 2, into which the casting material will be poured.
Basically, this stage of the process comprises the positioning of the casting model 1 with a molding container, in which the molding sand is loca- ted, and the removal of the aforesaid molding container. The molding containers, preferentially, have their superior and lower sections open, or empty.
Preferentially, in this stage, due to the fact that model 1 is bipartite, each of the halves of the casting model 1 is placed over a board, or flat surface, and then the molding containers are positioned over these boards con- taining the models. Next, the molding container is filled with molding sand, filling it and completely covering the halves of the casting model 1. Furthermore, a compacting procedure for the sand is performed so that the bulk of the refractory material enters into contact with the halves of the casting model 1 as close as possible, and so that the sand fills the entire bulk of the molding containers up to the limit established by the height of their sideframe surfaces.
After the filling with sand, each container is removed from the board containing the model. In this way, after removing the halves of the casting model 1 from the containers, a cavity of a complementary or negative format is obtained, in the format of model 1 , when the aforesaid containers are placed one on top of the other.
Normally the molding containers are placed horizontally, with a first half of the cavity, constituting a lower section, denominated as the bottom, and a second half positioned over the first, constituting a higher section, de- nominated as the top. Also, in these molds 2, channels are made, through which the liquid casting material can be poured, depending on its application to the geometry of the part, the work temperature and the alloy used.
Although the preference of this invention reflects a bipartite casting model 1 with two mold containers, other possibilities should not be excluded and this is not a restrictive factor to the scope of protection for the invention.
(iii) - Manufacture of the cores This stage can occur before or in parallel to the casting process. These two possibilities are not restrictive to the scope of protection for the present invention.
Cores are elements, normally made of special sands and produced in core containers, whose function is to fill the empty internal spaces in the mold. They produce cavities that the part to be cast, in this case the truck sideframe, will have after the end of the casting.
In the casting process of the present invention, the cores used preferentially are illustrated in figures 3A to 3D. In figure 3A, the cores of the first 4 and second 5 sideframe sections are illustrated and, as can be seen, these have a substantially analogous format to the format of the truck sideframe sections. Figure 3B illustrates the core 6 of a first area of connection 19 between the first 10 and the second 12 sideframe sections of the casting model 1. Figure 3C illustrates the cores 7,7' of a second area of connection 20 between the first 10 and second 12 sections of the sideframe sections of the casting model 1. It is important to note that the cores 7,7' of the second area of connection 20 are positioned above, because it is in this manner that they are placed in the casting mold 2 (the next stage of the process). Figure 3D illustrates the core adjacent to the base 8.
Also fabricated are auxiliary cores in the lower back area 40, illustra- ted in figure 3F, and the cores of the brake system guide 9, illustrated in figure 3E, which are responsible for producing a cavity capable of housing part of the truck brake system (brake shoe guides), when the sideframe is ready.
The format of the cores illustrated by the abovementioned figures is not a factor affecting the scope of protection for this invention. It is only im- portant to note that the abovementoned cores are those which are always present in the production process of truck sideframes. Furthermore, other cores can be supplied in addition to these, without affecting the concept of
the casting process of the present invention. The exception to the addition of cores is restricted to two specific types of cores (central and adjacent to the base), which will be explained later.
The prior art casting processes still require the fabrication and obvi- ously the use of at least three more cores, precisely those with larger dimensions, which are: at least one core for the central section of the casting model 1 ; and at least one base core for each base of the casting model 1. These cores, when employed in the casting process present certain disadvantages, one of them being that they are extremely bulky cores, making the production of these elements very expensive due to the quantity of special sand employed to obtain them. Moreover, casting sand is not easily disposed in the environment and the use of this material in the production of bulky cores is disadvantageous and causes environmental problems
In order to give an example of the waste of sand in the prior art pro- cess, compared to the process of the present invention, it is worth quoting the weight of the eliminated cores. The central core, in an industrially manufactured sideframe, has an average weight of 125 Kg, and each one of the two base cores has an average weight of 25 Kg. In other words, about 175 Kg of core sand is not required in the casting process of the present inventi- on.
Consequently, if one considers that the casting industry produces, for example, about one thousand railway cars each year, and considering that each car uses two trucks, and that each truck uses two sideframes, we have: 1 ,000 cars > 2,000 trucks > 4,000 sideframes, in other words, about four thousand sideframes are produced each year. Therefore, if 175 Kg of casting sand is economized for each truck side- frame, by their elimination there will be a saving of approximately 700,000 Kg (seven hundred thousand kilograms) or 700 t (seven hundred tonnes) of casting sand (175x4,000 = 700,000), which clearly demonstrates one of the se- veral advantages of the casting process of the present invention, compared to the prior art. In effect, it is obtained through the reduction of the core sand weight, a reduction in the labor required for the manufacture of the aforemen-
tioned cores, and the reduction in the storage area required for the cores.
Other disadvantages that these cores produce will be explained in the pouring of the casting material stage (stage v). This will reinforce the reasons why the casting process of the present invention has countless advantages through the elimination of these cores.
(iv) - Placement of the cores into the mold
After the manufacture of the mold 2 and after the fabrication of the necessary cores to form the empty spaces in the truck sideframe, the casting process, object of the present invention, proceeds to the stage of the place- ment of the cores into the mold 2. To resume, this is the positioning of the cores over the points of the mold 2, where the empty spaces or hollow zones are formed.
Figure 5 illustrates the mold 2 with the principal cores in place. Note that in this figure the core of the first sideframe section 4 and the core of the second sideframe section 5 of the casting model 1 , are positioned above the section of the mold 2, which corresponds, respectively, to the first and second sideframe sections 10 and 12 of the casting model 1. It is also noted that the cores of the first 6 and second 7,7' areas of connection between the first and second sideframe section 10 and 12 of the casting model 1 , are positioned above the sections of mold 2, which corresponds, respectively, to the first and second elements of the connection 19 and 20 of the casting model 1. Moreover, an additional connection core 7" is positioned over the other cores 7,7' placed between the cores 4 and 5 of the first and second sideframe sections 10 and 12. The core 8 adjacent to the bases is positioned in a section of the mold 2, which corresponds to an area denominated second tooth of base 17 of the casting model 1 of the present invention.
On the other hand, the cores of the brake system guide 9 are placed directly over the casing model 1 in a housing 23. When the model is removed from the mold, these cores 9 are already an integral part of the mold, without the need for subsequent fastening, avoiding problems of seating, dimensional variations, burrs and future reworking. Moreover, the cores of the brake system 9, because they are not placed in the mold at the same stage as the
other cores are placed, can be considered eliminated from the casting process of the present invention.
With respect to the positioning of the cores, in the prior art casting process, the core of the central section is placed between the cores 4 and 5 and between the connection cores 6 and 7,7'. Each base core is placed between the core 8 of the base support and the extremities of cores 4 and 5 of the sideframe sections. The connection cores 6 and 7,7' are positioned together with the core of the central section and between the cores of the sideframe sections 4 and 5. However, the use of these cores in the casting process leads to a series of disadvantages and considerable problems because there is no means of fastening them to the mold 2. These cores are placed so that they remain positioned above the areas designed for them, only supported by each other, which can generate gaps between them and lead to considerable disadvantages during the pouring stage of the casting material (stage v) (burrs due to the excess of casting material, or cavities due to the lack of it). (v) - Pouring of the casting material
This stage comprises the filling of the mold 2 and the cores placed in stage (iv), with the casting material, preferentially metallic alloy. The material in its liquid state pours through an entry channel until it reaches mold 2 which, after filling it, proceeds by a cooling/breathing channel to the exit, balancing the pressures of the casting material in the entrance and exit of the mold.
However, it is in this stage that the disadvantages of the prior art arise, due to the fact that the cores of the bases and the central section are part of the process. More specifically, taking into consideration that, as well as being very heavy, these cores are placed loosely above the mold, the casting material moving around them can cause them to move, leave their position, or even fill the gap between them. If a mold moves from its normal position during the pouring of the casting material, the result after the cooling of the material is the appearance of a defect known as a fault, which consists of an irregularity between the geo-
metry of the volume of the halves of the sideframe. Therefore, taking into account that the sideframe halves, after the metal cools down, must be symmetrical, not only for the question of visual appearance but also for their functionality linked to the geometry of the truck sideframe, and the phenomenon such as a fault cannot be corrected even after the finishing stage, this can result in the truck sideframe being scrapped.
In the situation where the metal flows between the gaps formed by the distance between the cores, a laborious stage of finishing is necessary due to the large presence of burrs in the recently cast sideframe. To avoid this problem, the process of the present invention eliminates the cores of the centre and the base from its stages because their presence, as has been seen, brings a series of disadvantages to the process.
Moreover, the displacement of these cores also causes a series of dimensional problems that require re-working or even the scrapping of the pro- duct, due its failure to adhere to the dimensions and tolerances specified in the design.
Also, with respect to the prior art process, the casting of the truck sideframe with a large number of cores produces an equally large risk of non- metallic inclusions. The probability of the cores suffering erosion, due to their sand mixing with the casting material that pours into the mold 2, is increased. These inclusions can lead to a weakening of the part and may result more easily in a fracture in one of the truck sideframes under high mechanical s- tress.
On the other hand, the casting process of the present invention, wi- thout using the cores of the base and the central section, has the advantage of producing a truck sideframe with the following advantages:
1) a substantial reduction in faults because the number of cores o- verall is reduced, therefore implying a lower possibility of the faults occurring;
2) a significant reduction in the number of burrs because there is no longer the possibility of the casting material pouring into the gap between the central and base cores, which form part of the prior art process;
3) reduction of non-metallic inclusions because the number of cores
is reduced, or rather, the sources that produce this error (the cores) are reduced.
4) low sand ratio of core/metal because the heavy cores used in the prior art process are eliminated in the process of the present invention. 5) better surface appearance because the cores of the bases and the central section are no longer in contact with cores 6 and 7,7' of the first and second areas of connection, so there is no possibility of the casting material pouring between these cores, reducing the number of burrs and guaranteeing the improvement of the surface appearance; and 6) improvement in the dimensional conditions of the cast sideframe due to the elimination of the variations caused by the cores, avoiding the reworking and scrapping of the parts.
7) It is not necessary to drastically alter the physical structure of the casting model or even make large changes in the already known casting pro- cess making, from an economic point of view, the truck sideframe produced by this invention extremely advantageous.
(vi) - Removing the mold
After the casting material has filled the mold, if is necessary to wait until the material has cooled down and solidified before the mold can be remo- ved.
In this stage, the sideframe cast by the pouring of the casting material in stage (v) is removed from the mold. It is important to be careful with respect to the core sand removal, in order not to leave any residues in the internal areas of the cast part. (vii) - Finishing
After the part has been removed from the mold, it is necessary that a stage of finishing be performed to eliminate any remaining surface imperfections that may exist.
One of these imperfections is the burr, which in many cases is produ- ced by the leaking of the casting material through the pouring channels, by respiration, by the space between the cores positioned in the mold, or by the poured alloy entering fractures in the mold. In the casting process of the pre-
sent invention, the time spent removing burrs is considerably reduced, when compared to the prior art, because the removal of the central and base cores significantly reduces the occurrence of burrs. Nevertheless, if it is necessary to remove burrs, a mechanical or other de-burring process can be performed on the sideframe.
Even without the burrs, there may still remain sand and a few small physical deformations on the sideframe of the truck, which can be removed using steel brushes, either manually or with a sander, sandpaper or, if necessary, sandblasting. Other finishing processes can be used such as heat treatment, if it is necessary to apply special characteristics to the part, and rectification to obtain a high degree of dimensional precision in the truck sideframe.
2) Casting model
The present invention also provides a casting model 1 , which is the basis for the elimination of the cores that occurs in the casting process of the present invention.
As can be seen from figure 2, the casting mold 1 has a format similar to a truck sideframe and comprises a first sideframe section 10, connected by a central section 11 , to a second sideframe section 12. As has been alre- ady stated, the casting model 1 of the present invention is bipartite, although only one of its halves is illustrated in figure 2.
With respect to the sideframe sections 10 and 12, it can be seen that these are symmetrical, parallel and diametrically opposite to each other. Each one comprises a supporting arm 13, connected to an elongated bolster 14. The aforesaid supporting arm 13 extends obliquely from an area of contact between one of the sideframe sections 10 and 12, and the central section 11 , in the direction of the elongated bolster 14. Each elongated bolster 14, extends from an area of contact between one of the sideframe sections 10 and 12, and the central section 11 , and extends in a direction pointing longi- tudinally outside the casting model 1. Each elongated bolster 14 comprises in its free extremity a first tooth of the base 16. In turn, the supporting arm 13 comprises, in the area in which it is connected to the elongated bolster 14, a
second tooth of the connected base 17, being spaced and substantially parallel in relation to the first tooth of the base 16, with a space of the base 18 between them.
In the casting model 1 of the prior art, the space of the base 18 loca- ted between the first and second teeth of the base 16 and 17, is filled by a cavity formation element to accommodate the core of the base (not illustrated), which, as the name suggests, produces a cavity in the area of the bases when the bases 2 are manufactured. Therefore, because the area of the base cannot have this cavity filled with the poured casting material, the casting model 1 of the prior art anticipates the placement of the base cores, consequently producing a process whose final product, in this case the truck side- frame, has a series of imperfections. The present invention eliminates these cavity forming elements of the bases of the casting model 1 , producing a new casting model 1 , as well as a renewed casting process, whose final product has significant advantages compared to the prior art.
With respect to the central section 11 , it can be observed that this comprises: a first connection element 19 connected in a contiguous manner to the elongated bolsters 14 of the first and second sideframe sections 10 and 12; and a second connection element 20 connected in a contiguous manner to the supporting arms 13 of the first and second sideframe sections 10 and 12. These connection elements 19 and 20 are parallel and spaced between themselves, producing a central space 21 between them and the sideframe sections 10 and 12.
Also, the casting model 1 of the present invention comprises a distan- cing extremity 22, which projects substantially outside the model 1.
Therefore, in order to remedy the problems found in the prior art, the casting model 1 of the present invention also eliminates the formation elements of the central cavity, making it unnecessary to use the central core in the casting process. Therefore, this elimination, allied to the removal of the base cavity formation elements, removes the need to use the cores of the central section and bases in the casting process.
Also, the sideframe sections 10 and 12, adjacent to the central section
11 and more specifically close to the second connection element 20, comprise housings 23, which as has been said, are designed to seat the cores of the brake system guide 9.
In the prior art casting model, there is only one locator in the housing 23 (not illustrated) for a future seating of the core of the brake system guide 9 in the mold. This produces all the inconveniences already previously mentioned with the existence of the cores positioned in the mold.
3) Truck sideframe
The present invention also provides a railway car truck sideframe whose principal characteristic is the fact that it is produced in accordance with the casting process of the present invention.
4) Railway car truck
The present invention also provides a railway car truck whose principal characteristic is the fact that it has two sideframes manufactured in ac- cordance with the casting process of the present invention.
5) Railway car
Finally, the present invention provides a railway car whose principal characteristic is that at least one of its truck sideframes is manufactured in accordance with the casting process of the present invention. Having described an example of the preferred design, it must be understood that the scope of the present invention has other possible variations, limited only by the content of the appended claims, and all possible modifications are included.