Lightweight fatigue resistant railcar truck, sideframe and bolster

Abstract

The sideframe and bolster of a railway car truck are constructed such that basic overall sideframe and bolster appearance is maintained, but the actual material it is constructed of is changed. The material used is changed from cast steel to an austempered metal, such as, cast austempered ductile iron; whereas cast iron has a density, 0.26 lbs/in{circumflex over ( )}3, which is approximately 8% less than steel, 0.283 lbs/in{circumflex over ( )}3. This immediately allows for a reduction in weight. A second benefit is that iron is easier to pour than steel and actually increases in volume, slightly, as metal cools compared to steel which shrinks. Efficient use of materials is improved, meaning less metal is used to make the same final shape, as a way of reducing the sideframe and bolster weight. Both factures combined allow for a lighter weight railway car truck, sideframe and bolster, while utilizing standard designs.

Claims

1. A bolster for a railcar truck, said bolster having a first end and second end and being constructed from austempered ductile iron having an alloy content that is greater than 4.0% and a carbon equivalent (CE) value of 4.3 to 4.73, wherein said austempered ductile iron includes a post inoculant containing a mixture of La, Ca, S and O and wherein said nodularity is at least 90%, and wherein said bolster has a Brinell hardness of about 302 to 460; wherein the minimum tensile strength is 130 ksi; wherein the minimum yield strength is 90 ksi; and wherein the minimum elongation in 2 inches is 2%.

2. The bolster of claim 1, wherein said bolster has a top wall, two sidewalls, and a web disposed between said sidewalls and below said top wall, said web connecting with said top wall at locations along said web, wherein said web comprises an interior web that is parallel to and central of said sidewalls, wherein said top wall, said sidewalls and said web have thicknesses between 0.25″-3.0″.

3. The bolster of claim 2, wherein said top wall, said sidewalls and said web have thicknesses between 0.6875″ to 2.25″.

4. The bolster of claim 2, wherein at least one of said top wall, said sidewalls or said web has a maximum thickness of 0.25″.

5. The bolster of claim 3, wherein at least one of said top wall, said sidewalls or said web has a maximum thickness of 0.6875″.

6. The bolster of claim 1, wherein said bolster has a top wall, two sidewalls, and a web disposed between said sidewalls and below said top wall, said web comprising an interior web that is parallel to and central of said sidewalls and connecting with said top wall at locations along said web, and wherein said walls and said web have a maximum thicknesses of 3.0″.

7. The bolster of claim 6, wherein each of said top wall, said sidewalls and said web has a maximum thickness of 2.25″.

8. The bolster of claim 5, wherein each of said top wall, said sidewalls and said web has a maximum thickness of 2.25″.

9. The bolster of claim 1, wherein said bolster is constructed from austempered ductile iron having a composition according to the following formula: TABLE-US-00003 Carbon 3.60-3.80% Silicon <2.60%; Copper 0.50-0.70% Manganese 0.35-0.45% Nickel <0.03% Chromium <0.05% Magnesium 0.030-0.050% Iron balance of the composition.

10. The bolster of claim 1, wherein said bolster is constructed from austempered ductile iron having a composition according to the following formula: TABLE-US-00004 Elements Percentage Range C Carbon 3.6% +/−0.20% Si Silicon 2.5% +/−0.20% Mg Magnesium (% S × 0.76) + 0.025% +/−0.005% Mn Manganese Max. section > ½″ 0.35% maximum +/−0.05% Max. section < ½″ 0.60% maximum +/−0.05% Cu Cooper 0.80% maximum +/−0.05% Ni Nickel 2.00% maximum +/−0.10% Mo Molybdenum 0.30% maximum +/−0.03% Sn Tin 0.02% maximum +/−0.003% Sb Antimony 0.002% maximum +/−0.0003%. P Phosphorus 0.02% maximum S Sulfur 0.02% maximum O Oxygen 50 ppm maximum Cr Chromium 0.10% maximum Ti Titanium 0.040% maximum V Vanadium 0.10% maximum Al Aluminum 0.050% maximum As Arsenic 0.020% maximum Bi Bismuth 0.002% maximum B Boron 0.0004% maximum Cd Cadmium 0.005% maximum Pb Lead 0.002% maximum Se Selenium 0.030% maximum Te Tellurium 0.003% maximum Iron Balance of formula

11. The bolster of claim 10, wherein said austempered ductile iron composition further includes a post inoculant.

12. The bolster of claim 11, wherein said post inoculant is selected from the group consisting of La, Ca, S and O, and mixtures thereof.

13. The bolster of claim 11, wherein said austempered ductile iron comprises molten ductile iron and alloys in accordance with said formula, wherein said post inoculant is introduced to said molten ductile alloy and alloys, and wherein said bolster is a casting of austempered inoculated ductile iron.

14. The bolster of claim 13, wherein said bolster has a minimum nodule count of 100 per mm2.

15. The bolster of claim 13, wherein said bolster has a top wall, two sidewalls, and a web disposed between said sidewalls and below said top wall, said web connecting with said top wall at locations along said web, wherein said web comprises an interior web that is parallel to and central of said sidewalls, and wherein said walls and said web have thicknesses between 0.25″-3.0″.

16. The bolster of claim 15, wherein said top wall, said side walls and said web have thicknesses between 0.6875″ to 2.25″.

17. The bolster of claim 15, wherein at least one of said top wall, said sidewall and said web has a maximum thickness of 0.25″.

18. The bolster of claim 16, wherein at least one of said top wall, said sidewall and said web has a maximum thickness of 0.6875″.

19. The bolster of claim 13, wherein said bolster has a top wall, two sidewalls, and a web disposed between said sidewalls and below said top wall, said web connecting with said top wall at locations along said web, wherein said web comprises an interior web that is parallel to and central of said sidewalls, and wherein said walls and said web have a maximum thickness of 3.0″.

20. The bolster of claim 19, wherein each of said top wall, said sidewalls and said web has a maximum thickness of 2.25″.

21. The bolster of claim 17, wherein each of said top wall, said sidewalls and said web has a maximum thickness of 2.25″.

22. The bolster of claim 13, having a minimum elongation in 2 inches of about 7%.

23. An improved railcar truck including: the bolster of claim 9, wherein said bolster has a wall thickness between 0.25″ and 3.0″; and a pair of sideframes connected to said bolster.

24. The improved railcar truck of claim 23, wherein each said sideframe is constructed from an austempered metal selected from the group consisting of austempered ductile iron, austempered steel, austempered metal alloys, and mixtures thereof; and wherein each said sideframe has a wall thickness between 0.25″ and 2.5″.

25. An improved railcar truck including: the bolster of claim 10, wherein said bolster has a wall thickness between 0.25″ and 3.0″; and a pair of sideframes connected to said bolster.

26. The bolster of claim 15, wherein said bolster has a minimum nodule count of 100 per mm2.

27. The bolster of claim 2, wherein at least one of said sidewalls, said top wall and said web has a thickness of 0.25″.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other objects and advantages of the present invention will become apparent from the following detailed descriptions taken in conjunction with the drawings wherein:

(2) FIG. 1 is a perspective view of a railway truck with a pair of sideframes and a bolster according to the present invention, shown without the wheelset;

(3) FIG. 2 is a top plan view of the truck of FIG. 1;

(4) FIG. 3 is a perspective view of the bolster of FIG. 1, according to the present invention, shown separately from the sideframe;

(5) FIG. 4 is a front elevation view of the truck sideframe of FIG. 1, according to the present invention, shown separately from the bolster.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) Preferred embodiments of the invention include railcar sideframes, bolsters and truck sets that are constructed to have improved properties, and, preferably, improved strength to weight ratios. The improved trucks constructed using the improved sideframes and bolsters, preferably have payload-to-weight ratios that are greater than prior trucks. Preferred embodiments of the trucks constructed using the sideframes and bolsters are produced from an austempered metal, such as, for example, austempered ductile iron.

(7) A preferred embodiment of a sideframe and bolster arranged in a configuration with a pair of sideframes 20, 24 and a bolster 16 forming a railcar truck 10, is illustrated in FIGS. 1-3. The sideframe 20, 24, bolster 16 and truck 10 embodiments illustrated in FIGS. 1-3 are exemplary embodiments, and, according to the present invention, alternate embodiments, including sideframes and bolsters, having different configurations may be constructed in accordance with the present invention. According to some preferred embodiments, the prior art geometry is maintained, and the components of the truck, such as, for example, the sideframes and bolsters are constructed from austempered metal.

(8) Referring now to FIG. 1, there is shown a railway vehicle truck 10 common to the railroad industry. Truck 10 comprises generally a pair of longitudinally spaced wheel sets (not shown), each set including an axle with laterally spaced wheels attached at each end of the axles in the standard manner. A pair of transversely spaced sideframes 20,24 is mounted on the wheel sets. The sideframes 20, 24, according to preferred embodiments, preferably are constructed from a material, such as metal, that has a specific gravity that is lower than that of steel, but provides suitable strength for the sideframes 20, 24, and preferably strength that is equal to or greater than steel. According to preferred embodiments, the sideframes 20, 24 are constructed from an austempered metal, and more preferably from austempered steel or austempered ductile iron. Alternately, the sideframes 20, 24 may be constructed from other austempered metals. According to a preferred embodiment, the sideframes 20,24 may be reduced in weight by about up to 8%, approximately 80 lbs each, when the austempered metal is austempered ductile iron, as cast iron has a density, 0.26 lbs/in{circumflex over ( )}3, which is approximately 8% less than steel, 0.283 lbs/in{circumflex over ( )}3. Embodiments of the present invention sideframes and bolsters, such as, for example, the sideframes 20,24, and bolster 16 may be constructed using austempered ductile iron. The sideframes 20,24 of the present invention preferably are lighter than prior sideframes of equal sizes and dimensions, yet possess similar or greater strength. Alternately, the sideframes 20,24 of the present invention may be constructed from an austempered metal, which may include austempered metals, austempered metal alloys, and, more preferably, may include austempered metals and austempered metal alloys having a specific gravity of about 0.26 lbs/in3. Austempered ductile iron is one preferred austempered metal. Additionally, the bolster 16, shown and described herein, may be constructed from the same materials as the sideframes 20,24, preferably austempered metal.

(9) According to preferred embodiments of the invention, exemplary embodiments of sideframes 20, 24 and bolster 16 are illustrated in FIGS. 1-4. In FIG. 1, the sideframes 20,24 are arranged with the bolster 16 to form a railcar truck 10 (the wheel sets not being shown). Sideframes 20,24 each include a bolster opening 26, respectively, in which there are supported by means of spring sets (not shown), a bolster 16. Bolster 16 extends laterally between each sideframe 20,24 and generally carries the weight of the railcar. Upon movement in the vertical direction, bolster 16 is sprung by spring sets (not shown) which are attached to a spring seat plate 25 at the bottom of sideframes 20,24. The bolster 16 preferably is of a standard configuration, with a geometry known in the art, but is constructed to be lighter in weight. According to preferred embodiments, the bolster 16 preferably is constructed from a material, such as an austempered metal having a specific gravity that is lower than that of steel, but which is equal to or greater than steel in strength. The bolster 16 may be composed from the materials described herein in connection with the sideframes 20,24. For example, according to a preferred embodiment, the bolster 16 may be reduced in weight by about up to 8%, approximately 140 lbs, when the austempered metal is austempered ductile iron, as cast iron has a density, 0.26 lbs/in{circumflex over ( )}3, which is approximately 8% less than steel, 0.283 lbs/in{circumflex over ( )}3. According to preferred embodiments, the sideframes 20,24 and bolster 16 may be constructed by any suitable casting process. The process for producing the sideframes and bolsters, such as, for example, the sideframes 20,24 and bolster 16, according to a preferred embodiment, involves producing austempered ductile iron by a suitable austempering process. For example, one process involves austempering of ductile iron by heat-treating cast ductile iron to which specific amounts of nickel, molybdenum, manganese or copper, or combination thereof have been added to improve hardenability.

(10) As previously mentioned, historical design considerations for addressing the sideframe compressive and tensile stress problems have largely involved increasing the cross-sectional thicknesses of the top and bottom members without regard to weight. According to the exemplary embodiment, a sideframe 20 is illustrated, and is constructed to be functionally stronger, yet use less metallic mass. The present invention is designed to improve upon prior sideframes, which, according to one preferred embodiment, provides an open, yet solid sideframe 20,24, that has an increased payload-to-weight ratio. Preferred embodiments provide a sideframe configuration that is constructed from an austempered metal, such as, for example, austempered ductile iron.

(11) According to preferred embodiments having the structure of the sideframe constructed as an open, yet solid, sideframe, a typical payload-to-weight ratio may be exceeded with the use of the preferred austempered metal sideframe composition.

(12) Since the sideframes 20,24 are identical members, only one of them will be described in greater detail. Referring now to FIGS. 1-2 and 4, a sideframe 20 incorporating the features of the present invention is shown and generally comprises an upper compression member flange 30, extending lengthwise of truck 10 and a lower tension member flange 40, also extending the length of truck 10. The compression member flange 30 and the lower tension member flange 40 may be solid members. Vertical web 50 extends between the upper flange 30 and the lower flange 40 and connects the upper and lower flanges together, thereby defining the overall structural shape of sideframe 20. According to one embodiment, a web may be provided on the opposite side (not shown), and the sideframe or portions thereof between the front web 50 upper flange 30 and lower flange 40, may be hollow, or may be partially hollow. Reviewing FIG. 4 in more detail, it is seen that lower tension member flange 40 has a midsection which is generally parallel to upper compression member 30, and it also has a front and rear section which is comprised of upwardly extending solid diagonal flange sections 60,70 for integrally connecting the lower flange 40 to the upper flange 30 at each sideframe end 29,31. Even though the sideframe flanges are constructed as one continuous flange member, the upper flange experiences compression loading during operation, while the lower flange experiences tensile loading. As shown in FIG. 4, according to one embodiment, vertical columns 80,90 may be provided to connect the upper and lower members together in order to add structural support and integrity to sideframe 20; the columns also may define the bolster opening 26. According to the embodiment illustrated in FIG. 4, one embodiment may include a construction where neither of the vertical columns 80,90 fully extends between the top and bottom members, although they still define the bolster opening. According to that alternate embodiment, columns 80 and 90 may extend vertically downward from top flange member 30, to spring seat plate 25, thereby forming a center U-shaped structure. According to preferred embodiments, springs (not shown) are seated on the spring seat plate 25 when the sideframe 20 is assembled with another sideframe 24 and bolster 16 to form a truck 10.

(13) According to one embodiment, the columns 80,90 may be integrally connected to upper flange member 30, and the spring seat plate 25 is suspended similar to a simply supported beam having an intermediate load and, according to one embodiment, optionally, in order to provide stability and strength to the columns 80,90 and/or the spring seat plate 25, lower support struts 120 may be provided that tie the plate 25 to vertical web 50 and lower flange 40. According to one embodiment, column reinforcing ribs 85,95 may be provided and added to columns 80,90 in order to tie the columns to vertical web 50.

(14) FIG. 4 also shows that each end 29 and 31 of sideframe 20 also includes a downwardly projecting pedestal jaw 35, respectively depending from each end. According to a preferred embodiment, it is at the pedestal jaw area where the flange of the top compression member 30 and the flange of the lower tension member 40 are ultimately connected together structurally. In the exemplary embodiment illustrated, structurally completing the jaw area is the L-shaped bracket member 65 depending downwardly from the pedestal jaw 35. The addition of each of the brackets thereby defines the axle-accommodating pedestal jaw opening 36 in which the axles 18 of the railcar ride. According to an alternate embodiment (not shown), optionally, the pedestal jaw roof 45 may be provided with pedestal jaw reinforcing gussets for connecting and supporting the jaw roof 45 to the vertical web 50. Shown in FIG. 4 are the brake beam guides 130. According to preferred embodiments, these guides 130 are only found on the inboard side of sideframe 20 and they retain the brake beams used to apply force to wheel sets when stopping the railcar. The guides 130 are shown having a slight downwardly angled horizontal pitch and they connect to the lower tension member diagonal flanges 60,70 on one end and to the vertical columns 80,90 on the other end. The inboard side of guide 130 is also connected to web 50, thereby adding structural support to the sideframe midsection.

(15) As mentioned, the top flange member 30 is known to undergo compression when the railcar truck is loaded while the bottom flange 40 undergoes a tensile loading. Moreover, it is well known that the very distal ends 29,31 of sideframe 20, namely at the pedestal jaws 35, are the least stressed areas of the sideframe and the forces acting on this area are mainly straight down, static loads, although there is some twisting or dynamic loading, but its occurrence is infrequent and is usually present only when the truck becomes out of square, as in turning. Furthermore, it is also well known that the center or midsection of the sideframe experiences the greatest magnitude of forces due to the loads transferred from the bolster 16 into the spring set groups. Since each end 29,31 of sideframe 20 is supported by the axles (not shown) and wheel sets (not shown), the midsection is effectively suspended between the two ends, making the static and dynamic loading, as well as twisting and bending moments, the greatest in the midsection area of the sideframe. The sideframe midsection therefore has to be structurally stronger than the distal ends 29,31, and the present sideframe has been specifically designed with that in mind.

(16) The sideframes 20,24 and bolster 16 may be constructed with a suitable thickness that will support the loads to be handled thereby. For example, the thickness of the flanges 30, 40 and web 50 may be sized so that the components, including when assembled together to form a truck, will have a desired load supporting strength.

(17) According to some embodiments, sideframes may be constructed with structural components that have hollow interiors. Although the exemplary sideframe 20 is shown having a solid vertical web 50, other sideframes, constructed in accordance with the present invention may be cast with structural components that have hollow interiors. Referring again to FIG. 4, it is seen that vertical web 50 contains a pair of lightener openings 200 on each end of the sideframe for further reducing the weight of the sideframe 20. Because it is well known that openings act as stress accumulation points, according to some embodiments, the web 50 may be provided with a lip (not shown) around the entire peripheral edge of lightener opening 200 for maintaining a relatively high section modules around the opening. Therefore, according to some sideframe embodiments shown in FIGS. 1-2, and 4, a lip, when provided, adds structural strength around lightener opening 200 and to sideframe 20, thereby increasing resistance to fatigue cracking from cyclic flexure stressing. According to one alternate embodiment, as a means for maximizing the section modules while minimizing the metallic mass being added, the lip may be configured so that it does not remain at a constant cross-sectional thickness around peripheral edge.

(18) According to a preferred embodiment, these minute details concerning metallic mass versus localized loading stresses have been carried out all throughout the exemplary sideframe design. For example, it is known that the greatest stresses occur at the midsection and become proportionately smaller along the distance to the pedestal jaw; therefore, according to some embodiments, the entire structure may be configured so that it is not as structurally large at ends 29,31 as it is in the midsection. According to some embodiments, the top and bottom flanges 30,40 may be designed to neck down or taper, starting from the point near the midsection and the vertical columns 80,90, outward towards the pedestal jaws in a quite extreme fashion in order to save weight. The top and bottom members 30,40 may decrease in width. For example, according to some embodiments, the sideframe may be constructed with a midsection width that is slightly larger with the distal ends 29,31 having a substantially smaller width, making each of the top and bottom flanges even lighter than traditional shaped sideframes.

(19) According to preferred embodiments, the midsection of the upper compression member area which is between the vertical columns 80 and 90 may also be configured for weight reduction. According to some alternate sideframe embodiments, lower tension members may be provided having structural cross-sectional profiles which are closed, box-like, hollow frames and the entire upper compression members may have similar structural profiles. According to a preferred embodiment, the sideframe 20 illustrated in FIGS. 1-2, and 4, may be constructed having a lower midsection that is structurally reinforced through the addition of lower support struts 120, and, in addition, the structural profile of the upper midsection between the vertical columns also may be reinforced.

(20) Referring to FIG. 3, a bolster 16 is illustrated, which, preferably, is constructed from an austempered metal, as discussed herein, and more preferably, austempered ductile iron. The bolster 16 has a box-like body 116 with top wall 117, and interconnecting side walls 118. Though not shown, the bolster 16 may also have a bottom wall or wall portions spanning between the side walls 118, which preferably may be disposed opposite the top wall 117. A pin receptor 119 is centrally located in top wall 117 and two distal ends 122,123 extend outwardly of the body 116 at a distance from receptor 119 beyond the side frames 20,24 (see FIG. 1) Each distal end 122,123 includes flat, horizontal, surfaces 124, 125 adapted to directly carry a rail car body (not shown) at or adjacent the side sills thereof. According to some embodiments, the bolster 16 may also include an interior web 126 parallel to and central of the side walls 118.

(21) In an alternate configuration, not shown, the surfaces 124,125 of distal ends 122,123 may be provided with seats to receive friction side bearings generally to permit controlled sliding movement between the bolster ends and the railcar body. One alternate embodiment, not shown, involves providing seats at the distal ends 122,123 that have a depression or concave spherical segment surfaces so as to receive convex concentric undersurfaces of bearings.

(22) According to preferred embodiments, the ends of the bolster 16 preferably incline inwardly from top to bottom (so as to be in keeping within the American Association of Railroads standard clearance line at track side).

(23) According to preferred embodiments, sideframes and bolsters are constructed from austempered ductile iron, and according to a preferred embodiment, they are formed from austempered ductile iron having a minimum tensile strength of 130 ksi, a minimum yield strength of 90 ksi, and a minimum elongation in 2 inches of 2%. Additionally, some preferred embodiments have a BHN (Brinell hardness number) within a range of about 302 to about 460. According to some more preferred embodiments, sideframes and bolsters are formed from austempered ductile iron having a minimum tensile strength of 190 ksi, a minimum yield strength of 160 ksi, and a minimum elongation in 2 inches of 7%. The sideframes and bolsters also may have a BHN within a range of about 302 to about 460. According to a preferred embodiment, the ADI is a 190/160/7 in a standard 1″ Y-block. In accordance with preferred embodiments, the ADI formed sideframes and bolsters have carbon equivalency (CE) range of from about 4.3 to about 4.73, and more preferably, has a CE range of from about 4.3 to 4.6. Since alloying elements other than carbon are used in the preferred embodiments, the carbon equivalency provides a value taking into account a conversion of the percentage of alloying elements other than carbon to the equivalent carbon percentage. Iron-carbon phases are better understood than other iron-alloy phases, so the carbon equivalency (CE) is used. A convenient method to accomplish this is to combine the elements of the chemical composition into a single number, equaling the carbon equivalent. There are a number of formulas for ascertaining carbon equivalency. Generally, three primary carbon equivalent formulae have been commonly used in prediction algorithms for hydrogen-assisted cracking of steels. These include: Pcm, CEIIW and CEN. According to preferred embodiments, preferred CE values for ADI used to construct the sideframes and bolsters is determined by: CE=% C+⅓ (% Si). According to preferred embodiments, the iron is alloyed with additional components, including those set forth in the formulas below. Preferred embodiments of the sideframes and bolsters are constructed from ADI that has an alloy content that is greater than 4.0%. Further preferred embodiments of the sideframes and bolsters are constructed from ADI having alloy content greater than 4.0% and a carbon equivalency value of 4.37 to 4.73.

(24) According to some preferred embodiments, ADI sideframes and bolsters are made in accordance with the following composition:

(25) TABLE-US-00001 Carbon Equivalent 4.37-4.73   Carbon 3.60-3.80% Silicon <2.60%; Copper 0.50-0.70% Manganese 0.35-0.45% Nickel <0.03% Chromium <0.05% Magnesium 0.030-0.050% Iron balance of the composition.

(26) In one proposed example, the above composition is cast in a mold to form a sideframe and in another mold to form a bolster. Cores, such as sand cores, may be used to define cavities that will be formed in the completed respective sideframe or bolster. The molten metal may be introduced into the mold cavity or cavities through one or more gates. When the molten metal has filled the mold cavities, and it is allowed to solidify. The sideframe or bolster casting is removed from the mold, and cores are removed from the respective casting, or broken apart if required for their removal. The sideframe and bolster castings are austempered through a series of heating and cooling steps. The cast iron is raised to a heating temperature above the Ae.sub.3 temperature, or above 910 degrees C. (Modern Physical Metallurgy, R. E. Smallman, A. H. W. Ngan, Chapter 12, Steel Transformations, p. 474, FIG. 12.1) After heating to above about 910 degrees C., the respective sideframe or bolster casting is then rapidly quenched and held at the lower temperature. According to this proposed example, the resultant sideframe and bolster formed from the composition and ADI, is a 190/160/7 ADI.

(27) According to preferred embodiments, the walls have carbon equivalent (CE) in a prescribed range. One way in which the carbon equivalent (CE) value is expressed, is CE=% C+⅓ (% Si). According to preferred embodiments, the CE range is about 4.3 to about 4.6. According to preferred embodiments, where the wall thickness is between about 0.25″ to 2″, the sideframe or bolster wall has a CE range of from about 4.3 to about 4.6, and where the wall is over 2″, then the CE range is between about 4.3 to 4.5. In addition, preferred embodiments of the ADI sideframe and bolster are constructed from casting that has minimum nodularity properties. According to preferred embodiments, the ADI sideframe and bolster castings have a minimum nodule count of 100/mm2 and minimum nodularity of 90%.

(28) According to another preferred formulation, the ADI casting is made from a composition as follows:

(29) TABLE-US-00002 Preferred Elements Percentage Control Range C Carbon 3.6% +/−0.20% Si Silicon 2.5% +/−0.20% Mg Magnesium (% S × 0.76) + 0.025% +/−0.005% Mn Manganese Max. section > ½″ 0.35% maximum +/−0.05% Max. section < ½″ 0.60% maximum +/−0.05% Cu Cooper 0.80% maximum (only as +/−0.05% needed) Ni Nickel 2.00% max. (only as needed) +/−0.10% Mo Molybdenum 0.30% max. (only as needed) +/−0.03% Sn Tin 0.02% max. (only as needed) +/−0.003% Sb Antimony 0.002% max. (only as needed) +/−0.0003% P Phosphorus 0.02% maximum S Sulfur 0.02% maximum O Oxygen 50 ppm maximum Cr Chromium 0.10% maximum Ti Titanium 0.040% maximum V Vanadium 0.10% maximum Al Aluminum 0.050% maximum As Arsenic 0.020% maximum Bi Bismuth 0.002% maximum B Boron 0.0004% maximum Cd Cadmium 0.005% maximum Pb Lead 0.002% maximum Se Selenium 0.030% maximum Te Tellurium 0.003% maximum Iron Balance of formula

(30) Iron being the balance of the composition, which may range from about 89 to about 95%.

(31) According to preferred embodiments, the sideframes and bolsters include at least some walls whose thicknesses are greater than ¾″. Some preferred embodiments are constructed from ADI of the above formulas, wherein hardening alloys are added to the ductile iron forming the casting so as to reduce pearlite formation during the austempering quenching step. Preferred hardening alloys include alloying elements, such as Mo, Cu and Ni. The hardening alloys may be added, preferably, in amounts less than or up to the maximum respective amount. For example, in the first listed formula set forth above, the hardening alloys may be added to the formula up to the maximum amounts specified in the second listed formula (above).

(32) According to preferred embodiments, the ADI sideframes and bolsters may be formed with an ADI alloy that contains nodulizing elements. One example of a preferred embodiment, includes Mg as a nodulizing element. In addition, according to alternate embodiments, other examples of nodulizing elements, include beryllium, calcium, strontium, barium, yttrium, lanthanum and cerium. Although Mg is used in preferred embodiments, in other embodiments an alternative nodulizing element or combination of elements may be used. According to preferred embodiments, the amount of residual Mg plus the amounts of other nodulizing elements (e.g., beryllium, calcium, strontium, barium, yttrium, lanthanum and cerium) is less than or up to about 0.06%. According to some preferred embodiments, Ce may be used as an alloy to facilitate nodulization. According to some preferred embodiments, the ADI sideframes and bolsters are produced by forming a ductile iron casting, and subjecting the casting to an austempering process of elevated temperatures and quenching. The ADI sideframe and bolsters according to the invention are produced to have high nodularity and nodule formation throughout the solidification of the ADI bolster and sideframe ADI castings, which is preferably done using an inoculant. According to preferred embodiments, a mixture of La, Ca, S and O is provided in the inoculant. The inoculant may be referred to as a post inoculant, as the ductile iron may be alloyed with one or more alloy elements, and, the inoculant may be a separate addition, added to the molten ductile iron/alloy or mold to which the molten ductile iron/alloy is being added. The sideframe and bolster of the invention preferably are produced using ductile iron, to which small amounts of other elements have been added, as discussed herein, and to include in the addition thereto, preferably, at the molten stage of the ductile iron/alloy, an inoculant. The inoculant preferably is an element or combinations of elements that increase nodule formation. According to a preferred embodiment, the inoculant is selected from the group consisting of La, Ca, S and O (and mixture thereof). The inoculant may be added to the stream of molten metal (the molten ductile iron and alloy components) as it is poured into the mold. Alternatively, the inoculant is added to ductile iron by adding the inoculant in the mold. Preferred embodiments of the ADI bolsters and sideframes are produced from inoculated ductile iron (by an addition of the inoculant to the molten material as it is being admitted to the mold, or introducing the inoculant to the mold into which the molten ductile iron is to be admitted). The inoculated ductile iron casting is then austempered. The increased nodule formation and high nodularity throughout the improved sideframes and bolsters provides improvements in strength, particularly an increase resistance to fatigue and cracking.

(33) According to embodiments, the sideframes and bolsters are constructed having a high nodule count, high nodularity, or both. According to some preferred embodiments, the nodularity and nodule count may be optimized. Sideframes and bolsters according to preferred embodiments are constructed having a minimum nodule count, which may be expressed in a number of nodules per unit of area. For example, according to some preferred embodiments, the ADI sideframes and bolsters are constructed having a nodule count that is at least 90 per mm2, and preferably, at least 100 per mm2. Some preferred embodiments of the ADI sideframes and bolsters are provided having nodularity that is a minimum of 80%, and more preferably, at least 90%. According to some preferred embodiments, bolsters and sideframes are constructed from ADI and have, both a nodule count that is at least 90 per mm2, and preferably, at least 100 per mm2, and also have nodularity that is a minimum of 80%, and more preferably, at least 90%.

(34) According to preferred embodiments, the wall thicknesses of the sideframe, bolster and truck assembly including them may be constructed to be lighter, yet at the same time, impart suitable strength characteristics. The invention further provides embodiments of bolsters, sideframes and trucks with improved constructions having walls that have thicknesses that allow for improved configurations.

(35) The sideframe 20,24 are constructed being formed from walls. According to some preferred embodiments, the upper flange 30 and lower flange 40 are formed by walls. The walls generally have a thickness, and may define a space therebetween, with one side of the wall forming the flange being an exterior wall. The web 50 has a thickness and may be comprised of a wall having the same or different thickness as one of the upper or lower flanges 30,40, or both. According to some embodiments, the wall thickness of the flanges 30,40 and web 50 may be the same, and according to other embodiments, one or more of the walls defining the flanges 30,40 or web may be different. The spring seat 25 also may be constructed from a wall having a preferred thickness. According to some embodiments, the wall thicknesses of walls forming the side frame may be the same, and in other embodiments, the wall thicknesses of the walls forming the sideframe may be different.

(36) Preferred embodiments of a sideframe 20,24 are constructed from austempered ductile iron, and have a preferred wall thickness of from about 0.25″-2.5″, and more preferably, from about 0.375″ to about 1.75″. The wall thicknesses are for the sideframe walls, and may include one or more of the walls forming the flanges 30,40, webs 50, spring seat 25, and jaw roof 45. According to some preferred embodiments, the sideframe 20,24 is constructed so that at least one wall has a maximum thickness of about 0.375″. According to another preferred embodiment, the sideframe 20,24 is constructed so that at least one wall has a maximum thickness of about 0.25″. According to some preferred embodiments, the sideframe 20,24 is constructed so that the walls have a maximum thickness of about 2.5″. According to another preferred embodiment, the sideframe 20,24 is constructed so that the walls have a maximum thickness of about 1.75″. Other preferred embodiments include sideframe embodiments where at least one wall has a maximum thickness of 0.25″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 2.5″. Still other preferred embodiments include sideframe embodiments where at least one wall has a maximum thickness of 0.25″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 1.75″. According to yet other preferred embodiments, the sideframe 20,24 has at least one wall with a maximum thickness of 0.375″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 2.5″. Still other preferred embodiments include sideframe embodiments where at least one wall has a maximum thickness of 0.375″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 1.75″.

(37) The bolster 16 is shown having a plurality of walls, including a top wall 117, interconnecting side walls 118, and a wall or web 126. Preferred embodiments of a bolster 16 are constructed from austempered ductile iron, and have a preferred wall thickness of from about 0.25″-3.0″, and more preferably, from about 0.6875″ to about 2.25″. According to some preferred embodiments, the bolster 16 is constructed so that at least one wall has a maximum thickness of about 0.6875″. According to another preferred embodiment, the bolster 16 is constructed so that at least one wall has a maximum thickness of about 0.25″. According to some preferred embodiments, the bolster 16 is constructed so that the walls have a maximum thickness of about 3.0″. According to another preferred embodiment, the bolster 16 is constructed so that the walls have a maximum thickness of about 2.25″. Other preferred embodiments include bolster embodiments where at least one wall has a maximum thickness of 0.25″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 3.0″. Still other preferred embodiments include bolster embodiments where at least one wall has a maximum thickness of 0.25″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 2.25″. According to yet other preferred embodiments, the bolster 16 has at least one wall with a maximum thickness of 0.6875″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 3.0″. Still other preferred embodiments include bolster embodiments where at least one wall has a maximum thickness of 0.6875″ and the remaining walls are within a thickness range where the maximum wall thickness for any walls is 2.25″. The walls forming the bolster (e.g., the top wall 117, side walls 118 and web 126) may be constructed to have thicknesses within the ranges and preferred ranges discussed herein. According to some preferred embodiments, the walls forming the bolster 16 may have the same or different thicknesses from other walls forming the bolster 16.

(38) According to preferred embodiments of the invention, sideframes, bolsters and trucks are constructed from an austempered metal, preferably austempered steel, austempered ductile iron, austempered steel alloy or austempered ductile iron alloy. Preferred compositions, such as steel, as well as alloy steel compositions, e.g., alloyed preferably with magnesium, manganese, molybdenum, copper or mixtures thereof, or more preferably, with chromium, nickel or mixtures thereof, (or mixtures of the preferred and more preferred metals), may be used to form the sideframes and bolsters (which are assembled to construct a railroad vehicle truck) as discussed herein. The steel or preferred/more preferred alloy steel composition is austempered to obtain tensile strength, yield, and elongation properties for the inventive sideframes and bolsters (and trucks constructed therefrom) which are suitable to meet or exceed the AAR standards for sideframes, bolsters and trucks, including the current standard set forth by the American Association of Railroads (AAR) in AAR Manual of Standards and Recommended Practices, such as Specification M-976 (truck performance for rail cars) and Rule 88 of the AAR Office Manual, the compete contents of which are herein incorporated by reference. Sideframes and bolsters (and trucks made from these components) may be constructed from ductile iron that is austempered. The ductile iron also may be used in alloy form, preferably, with nickel, molybdenum, manganese, copper, or mixtures thereof, and the ductile iron alloy austempered to form sideframes and bolsters. The sideframes and bolsters may be used to form rail car trucks. The sideframes and bolsters formed from austempered ductile iron and from the preferred austempered ductile iron alloys (as well as the trucks constructed from these sideframes and bolsters), meet or exceed the AAR standards, including the current standard M-976 and Rule 88 of the AAR Office Manual. Lightweight sideframes, bolsters and trucks are constructed from austempered ductile iron, austempered ductile iron alloy, austempered steel, and/or austempered steel alloy, in accordance with the invention, to provide sideframes, bolsters and/or trucks that are lighter in weight than prior sideframes and bolsters (and trucks constructed therefrom) yet possesses suitable strength, yield and elongation properties that meet or exceed AAR testing and standards requirements.

(39) The foregoing description has been provided to clearly define and completely describe the present invention. Various modifications may be made without departing from the scope and spirit of the invention, which is defined in the following claims.