AU2011293392B2

AU2011293392B2 - Systems and methods for weight transfer in a vehicle

Info

Publication number: AU2011293392B2
Application number: AU2011293392A
Authority: AU
Inventors: Munishwar Ahuja; Amit Kalyani; Ravi Kumar; Mandyarm Sridhar; Nikhil Subhaschandra Tambe; Bret Worden
Original assignee: GE Global Sourcing LLC
Current assignee: Transportation IP Holdings LLC
Priority date: 2010-08-26
Filing date: 2011-08-25
Publication date: 2015-08-20
Anticipated expiration: 2031-08-25
Also published as: WO2012027520A1; EA026194B8; EA026194B1; AU2011293392A1; EA201390167A1; CA2808434A1; MX2013002269A

Abstract

Systems (142) and methods for weight transfer in a vehicle (100) are provided. One system (142) includes a plurality of springs (132) and a plurality of moveable spring seats (138) configured to adjust a length of the plurality of springs (132). Additionally, an actuator (170, 1170) is provided that is connected to the plurality of moveable springs (132) and configured to move the moveable spring seats (138) to adjust the length of the plurality of springs (132). Further, a controller (114) is provided that is coupled to the actuator (170, 1170) to control the actuator (170, 1170) to adjust the length of the plurality of springs (132).

Description

SYSTEMS AND METHODS FOR WEIGHT TRANSFER IN A VEHICLE BACKGROUND OF THE INVENTION [0001] Vehicles, such as diesel-electric locomotives, may be configured with truck assemblies including two trucks per assembly, and three axles per truck, for example. The three axles may include at least one powered axle and at least one non powered axle. The axles may be mounted to the truck via lift mechanisms, such as suspension assemblies including one or more springs, for adjusting a distribution of locomotive weight (including a locomotive body weight and a locomotive truck weight) between the axles. [0002] As the vehicle travels along the rails, the amount of load on each of the axles of the truck can vary, with each axle also having a maximum load weight. In certain conditions, such as during inclement weather, proper traction with the track may be lost, thereby resulting in one or more wheels slipping. Accordingly, the tractive effort for these vehicles may be less than optimized. For example, the tractive effort may be affected on trains, particularly for heavy trains or hauls, during start-up, on inclines, and during adverse rail conditions, such as caused by inclement weather or other environmental conditions. [0003] In known rail vehicle systems, the springs of the suspension systems for the trucks are preloaded. For example, each of the springs is preloaded based on a normal amount of weight to be supported by the suspension system for the axles. As a result, under certain conditions, the preloaded springs may not provide the sufficient normal force to maintain proper contact between the wheels of the truck and the track, especially during inclement or adverse rail conditions. [0003a] A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that the document or matter was 1 known or that the information it contains was part of the common general knowledge as at the priority date of any the claims. BRIEF DESCRIPTION OF THE INVENTION [0004] According to an aspect of the present invention, there is provided a vehicle suspension system, comprising: a plurality of springs; a plurality of moveable spring seats configured to adjust a length of the plurality of springs; a pneumatic actuator connected to the plurality of moveable spring seats and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the plurality of springs comprise outer axle springs and inner axle springs, and wherein the plurality of movable spring seats are coupled only to the inner axle springs. [0004a] According to another aspect of the present invention, there is provided a vehicle system, comprising: a frame configured to receive a plurality of axles, each of the axles having a corresponding spring suspension system with a plurality of springs; a traction motor coupled to at least some of the plurality of axles; a plurality of moveable spring seats configured to adjust a length of the plurality of springs to change a preloading of the springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the traction motors are coupled only to outer axles and the pneumatic actuator is coupled to an outside of the frame in connection with a center axle. [0004b] According to still another aspect of the present invention, there is provided a method for dynamically redistributing weight in a vehicle, the method comprising: configuring a plurality of springs of a vehicle suspension system for variable 2 preloading; mounting a preloading mechanism with the plurality of springs to the vehicle, the preloading mechanism having a pneumatic actuator; and controlling a length of the plurality of springs to provide variable spring preloading and load redistribution among axles of the vehicle; and controlling the length of the springs in a center suspension connected to a center axle not having a traction motor and wherein outer suspensions connected to outer axles include traction motors. [0004c] According to yet another aspect of the present invention, there is provided a vehicle suspension system, comprising: a plurality of springs; a plurality of moveable spring seats configured to adjust a length of the plurality of springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the pneumatic actuator comprises a lever configured to rotate a camshaft using a pair of cylinders pivotally connected to the lever, wherein rotation of the camshaft rotates a cam that translate the plurality of moveable spring seats. [0004d] According to still another aspect of the present invention, there is provided a vehicle system, comprising: a frame configured to receive a plurality of axles, each of a frame configured to receive a plurality of axles, each of the axles having a corresponding spring suspension system with a plurality of springs; a traction motor coupled to at least some of the plurality of axles; a plurality of moveable spring seats configured to adjust a length of the plurality of springs to change a preloading of the springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the pneumatic actuator comprises a cam arrangement configured to translate rotational movement of a level 2a actuated by a pair of cylinders to linear movement of the plurality of moveable spring seats. BRIEF DESCRIPTION OF THE DRAWINGS [0005] The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below: [0006] Figure 1 is a diagram of a vehicle formed in accordance with one embodiment. [0007] Figure 2 is a side view of a vehicle having trucks with variable spring preloaded suspensions in accordance with various embodiments. [0008] Figure 3 is a diagram of a spring preloading mechanism with actuation in accordance with various embodiments. [0009] Figure 4 is a schematic block diagram of a variable spring preload arrangement in accordance with one embodiment. 2b WO 2012/027520 PCT/US2011/049033 [0010] Figure 5 is a perspective view of an actuator formed in accordance with one embodiment; [0011] Figure 6 is a cross-sectional view of an actuator formed in accordance with one embodiment; [0012] Figure 7 is a perspective view of the actuator of Figures 5 and 6 in a normal operating state; [0013] Figure 8 is a perspective view of the actuator of Figures 5 and 6 is a weight redistribution state; [0014] Figure 9 is a top plan view of a vehicle having an actuator formed in accordance with various embodiments; [0015] Figure 10 is a side elevation view of the vehicle of Figure 9; [0016] Figure 11 is a perspective view of a mounting arrangement for an actuator in accordance with various embodiments; [0017] Figure 12 is a flowchart of a method to dynamically redistribute weight in a vehicle in accordance with various embodiments; [0018] Figure 13 is a diagram of a spring preloading mechanism with actuation in accordance with another embodiment; [0019] Figure 14 is a perspective view of an actuator formed in accordance with another embodiment; [0020] Figure 15 is a perspective view of a gearing arrangement of the actuator of Figure 14; 3 WO 2012/027520 PCT/US2011/049033 [0021] Figure 16 is a perspective view of a spring seat arrangement of the actuator of Figure 14; [0022] Figure 17 is a perspective view of a spring cap and power screw of the actuator of Figure 14; [0023] Figure 18 is a perspective view of an actuator formed in accordance with another embodiment; [0024] Figure 19 is a schematic block diagram of a power screw arrangement of the actuator of Figure 18; [0025] Figure 20 is a schematic block diagram of the actuator shown in Figure 18; and [0026] Figure 21 is a schematic block diagram of a guiding and locking mechanism of the actuator shown in Figure 18. DETAILED DESCRIPTION OF THE INVENTION [0027] To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between components. Thus, for example, one or more of the functional blocks may be implemented in a single piece of hardware or multiple pieces of hardware. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. [0028] As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to "one 4 WO 2012/027520 PCT/US2011/049033 embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property. [0029] It should be noted that although one or more embodiments may be described in connection with powered rail vehicle systems having locomotives with trailing passenger or cargo cars, the embodiments described herein are not limited to trains. In particular, one or more embodiments may be implemented in connection with different types of vehicles including wheeled vehicle, other rail vehicles, and track vehicles. [0030] Example embodiments of one or more apparatus and methods for changing the load of the axles to redistribute the load on the axles of a truck in a vehicle are provided. As described below, one or more of these embodiments provide dynamic weight transfer among the axles, for example, to redistribute the load to provide more load on the powered axles. By practicing the various embodiments, and at least one technical effect is increased traction on the powered axles, which may facilitate the tractive effort during certain traction limited modes of operation. Moreover, by practicing the various embodiments, less traction motors may be used to generate the same amount of tractive force or effort. For example, on a six axle truck, traction motors may be provided on only four of the axles instead of all six axles. Additionally, by practicing the various embodiments, improved braking may be provided. [0031] Figure 1 is a diagram of a powered rail vehicle 100 formed in accordance with one embodiment, illustrated as a locomotive system. While one embodiment of the presently described subject matter is set forth in terms of a powered rail vehicle, alternatively the subject matter may be used with another type of vehicle as 5 WO 2012/027520 PCT/US2011/049033 described herein and noted above. The rail vehicle 100 includes a lead powered unit 102 coupled with several trailing units 104 that travel along one or more rails 106. In one embodiment, the lead powered unit 102 is a locomotive disposed at the front end of the rail vehicle 100 and the trailing units 104 are cargo cars for carrying passengers and/or other cargo. The lead powered unit 102 includes an engine system, for example, a diesel engine system 116. The diesel engine system 116 is coupled to a plurality of traction motors 110 that provide the tractive effort to propel the rail vehicle 100. For example, the diesel engine system 116 includes a diesel engine 108 that powers traction motors 110 coupled with wheels 112 of the rail vehicle 100. The diesel engine 108 may rotate a shaft that is coupled with an alternator or generator (not shown). The alternator or generator creates electric current based on rotation of the shaft. The electric current is supplied to the traction motors 110, which turn the wheels 112 and propel the rail vehicle 100. It should be noted that for simplicity and ease of illustration, the traction motors 110 are only shown in connection with one set of wheels 112. However, traction motors 110 may be provided in connection with other wheels 112 or sets of wheels 112 as described herein. [0032] The rail vehicle 100 includes a controller, such as a control module 114 that is communicatively coupled with the traction motors 110 and/or an actuator 117 for controlling the load on springs 132 of a suspension system 142 (both shown in Figures 3 and 13). For example, the control module 114 may be coupled with the traction motors 110 and/or the actuator 117 by one or more wired and/or wireless connections. The control module 114 operates in some embodiments to control and redistribute the load supported by the each of the wheels 112, and more particularly, each axle 118. In various embodiments, dynamic load distribution may be independently provided to each of the axles 118. For example, each of the units 102 and 104 may include two sets of wheels 112 corresponding to two trucks 120 (shown more clearly in Figure 2). As illustrated, each truck 120 includes three axles 118, with each having two wheels 112. In some 6 WO 2012/027520 PCT/US2011/049033 embodiments, the outer axles 1 I8a and 11 8c are each powered by a traction motor 110, with the inner axle 11 8b not powered by a traction motor 110. Accordingly, for a particular unit 102 or 104, traction motors 110 are provided in connection with a total of four axles 118 instead of all six axles 118. It should be noted that the number of traction motors 110 and which axles 118 are connected to the traction motor 110 may be modified such that different configurations of tractive power may be provided. [0033] The control module 114 may include a processor, such as a computer processor, controller, microcontroller, or other type of logic device, that operates based on sets of instructions stored on a tangible and non-transitory computer readable storage medium. The computer readable storage medium may be an electrically erasable programmable read only memory (EEPROM), simple read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), FLASH memory, a hard drive, or other type of computer memory. [0034] Thus, as illustrated by the locomotive 122 shown in Figure 2, weight transfer or redistribution may be provided, such as when the wheels 112 are slipping relative to the rails (e.g., track) 106. In accordance with various embodiments, weight redistribution is provided, such that weight from the inner or middle axle 118b is redistributed to the outer axles 118a and 118c, illustrated by the larger arrows corresponding to the outer axles 118a and 118c and the smaller arrow corresponding to the inner axle 118, which represents a change in the weight or load on each of the axles 118a-c. The increased weight on the outer axles 118a and 118c results in increased traction of the wheels 112 of the axles 118a and 118c with the rails (e.g., track) 106, which reduces the amount of wheel slip, such as during traction limited modes of operation. Thus, the control module 114 may provide dynamic weight redistribution among the axles 118a-c. It should be noted that weight redistribution may be provided in connection with any unit of the rail vehicle system. 7 WO 2012/027520 PCT/US2011/049033 [0035] The weight redistribution in some embodiments includes a transfer of the weight from the inner axle 118b equally to the outer axles 118a and 118c. The weight redistribution is provided by changing the preload of springs in connection with one or more of the axles 118a-c. For example, in some embodiments, four springs are provided per axle 118a-c. However, the redistribution of weight is achieved by changing the preload of some, but not all of the springs. [0036] Various embodiments redistribute weight among the axles 118a-c by changing a spring length, for example, a working spring length. Thus, a preload on the spring is changed such that variable spring displacement is provided. For example, in embodiments illustrated in Figures 3 and 13, a variable spring preload arrangement 130 is illustrated forming part of a suspension system 142. It should be noted that like numbers represent like parts in the Figures. The variable spring preload arrangement 130 includes a mechanism for changing a preload of one or more springs 132 of the suspension system 142 of the truck 120 (shown in Figure 2), a portion of which is shown in each of the embodiments illustrated in Figures 3 and 13. An axle box 134 (which also may be referred to as a journal box) is provided having an opening 136 therethrough for receiving an axle, such as the axle ll8a-c of the locomotive 122 (both shown in Figure 2) extending also through the wheel 112. In the illustrated embodiment, two springs 132 are provided in connection with each axle side. [0037] In one or more embodiments, as shown in Figures 3 and 13, the mechanism for changing the preload of the springs 132 and thereby adjusting the working length of the springs 132 is a spring seat 138. It should be noted that although the spring seat 138 is shown at a top end of the springs 132, the spring seat 138 may be located on a bottom end of the springs 132. In the illustrated embodiment, the bottom or lower end of the spring 132 may be supported on the axle box 134 using, for example, a spring cap or other suitable means. Thus, the variable spring preload arrangement 130 in some embodiments includes a mechanism wherein a top end of the springs 132 is moveable to 8 WO 2012/027520 PCT/US2011/049033 provide the adjustable preloading and the bottom end of the springs 132 is fixed against the axle box 134. [0038] In the embodiments shown in Figures 3 and 13, one of the springs 132 (the right side spring 132) is shown without the spring seat 138 attached. The spring seat 138 may include a coupling end 140 to allow controllable actuation of the variable spring preload arrangement 130, such as by the control module 114 (shown in Figure 1). The controllable actuation in one embodiment is provided using an pneumatic actuation system 150 shown in Figure 3 and as described in more detail below and which may form part of the actuator 117 (shown in Figure 1). In another embodiment, the controllable actuation is provided using an electromechanical actuation system 1150 shown in Figure 13 and as described in more detail below and which may form part of the actuator 117 (shown in Figure 1). The actuation systems 150, 1150 may be implemented in different configurations and arrangements, as well as positioned at different locations of the truck. [0039] With respect to the actuator system 150 shown in Figure 3, and as one example, one or more pneumatic cylinders 180 may be provided with a rotating cam arrangement as described in more detail herein such that rotational movement is translated to linear movement of the spring seat 138. Moreover, a mechanical advantage may be provided using different configurations of the actuation mechanism, for example, using a lever as described in more detail herein. For example, in some embodiments, a mechanical advantage of 1:1.5 may be provided. However, it should be noted that different ratios of mechanical advantage may be provided depending on the configuration. [0040] With respect to the actuator system 1150 shown in Figure 13, and as another example, a splined shaft 1152 may be provided in connection with a geared motor 1154, which translates rotational movement of the motor 1154 to linear movement of the spring seat 138. Thus, a mechanical advantage is provided wherein linear 9 WO 2012/027520 PCT/US2011/049033 translation of rotational movement causes a change in the preloading of the springs 132. Moreover, a mechanical advantage may be provided using different configurations of the actuation mechanism, for example, using a lever mechanism as described in more detail herein. For example, in some embodiments, a mechanical advantage of 1:4 is provided, which is in addition to any mechanical advantage provided by the gear ratio of the geared motor 1152. However, it should be noted that different ratios of mechanical advantage may be provided depending on the configuration or arrangement. Thus, the gear provides an initial mechanical advantage and the lever provides an advantage once the rotational motion is converted to translational motion. [0041] The preload and effective pre-compression of the springs 132 may be dynamically adjusted, which affects the working length of the springs 132 and the load on the axle 118. In some embodiments, the changing of the preloading of the springs 132 may be initiated based on a user input, for example, based on a user identifying a traction limited mode of operation (e.g., wheel slipping or upcoming rail incline or adverse rail condition). In other embodiments, the changing of the preloading of the springs 132 may be initiated automatically, for example, based on a sensed or detected traction limited mode of operation using one or more sensors. In these embodiments, upon detecting the traction limited mode of operation or an upcoming traction limited mode of operation, such as based on an identification of the traction limited mode of operation by the sensor, which is communicated to the control module 114, the control module 114 automatically changes the preloading of the springs 132. A notification of the automatic preloading change may be provided to an operator, such as via an audible and/or visual indicator. [0042] In the embodiment shown in Figure 3, the control module 114 instructs the pneumatic actuation system 150 to change the preloading of the springs 132, for example, by operating the one or more pneumatic cylinders 180, which causes a linear translation of the spring seat 138. With respect to the embodiment shown in Figure 13, the control module 114 instructs the electromechanical actuation system 1150 to change 10 WO 2012/027520 PCT/US2011/049033 the preloading of the springs 132, for example, by operating the motor 1154 to linearly translate the spring seat 138. The translation of the spring seat 138 that changes the preloading and working length of the springs 132 redistributes the load among the axles 118 (shown in Figures 1 and 2). For example, the pneumatic actuation system 150 or the electromechanical actuation system 1150 may cause the spring seats 138 to move vertically downward to compress the springs 132 to shorten the working length of the springs 132 or move vertically upward to lengthen the working length of the springs 132 as illustrated in Figure 4. If the spring seats 138 are moved vertically upward, the working length of the springs 132 is increased or lengthened, which reduces the preloading of the springs 132. The reduction in the preloading of the springs 132 causes a shift in the weight among the axels 118 (shown in Figures 1 and 2), namely to the other axles 118. [0043] More particularly, referring to the example in Figure 4, showing a portion of a truck frame 160, if the preloading of the springs 132 of the center axle 11 8b is reduced by lengthening the springs 132, the weight or load is transferred or redistributed from the center axle 118b to the outer axles 118a and 118c (the axles 118a, 118b and 118c are shown in Figures 1 and 2). The outer springs 132a and 132c correspond to the outer axles 118 a and 118c and the inner springs 132b correspond to the inner axles 118b. The weight redistribution is equal when the change in spring preloading is the same. Accordingly, weight redistribution is provided by moving the spring seats 138 to change the preloading of the springs 132. It should be noted that in this embodiment, the spring seat 138 is illustrated at the bottom end of the springs 132. Also, in the illustrated embodiment, the spring seats 138 are shown on the springs 132b and not the other springs 132a and 132b. However, the spring seats 138 and consequently the control of the preloading may also be provided to the other springs 132a and/or 132b and at different locations or ends of the springs. 11 WO 2012/027520 PCT/US2011/049033 [0044] The spring seats 138 may be any suitable device for engaging and abutting an end of the springs 132 for translating the springs 132. For example, the spring seats 138 may be a washer or other end support for the springs 132, such as a support plate. Additionally, the springs 132 may be any type of spring, such as any spring suitable for a locomotive suspension. [0045] In an initial state of preloading, such as during a normal operating mode when a traction limited mode of operation is not detected, all of the springs 132a, 132b and 132c are preloaded the same. Thus, all of the springs 132a, 132b and 132c have the same or about the same working length. As the working length of the center springs 132b, which is an effective length of the springs, is increased, the net preload on the inner axle 11 8b (center axle) changes and the load or weight is redistributed to the outer axles 118a and 118c. [0046] As an example, if the rated load of each of the three axles 11 Sa, 11 8b and 11 8c is 70,000 pounds (also referred to as 70,000 pounds-force (lbf)), the axles I18a, 118b and 118c may be precompressed to have the same preloading. In this normal operating state, the working length of the springs 132a, 132b and 132c may be about 20.5 inches. In such an embodiment, the limits of the springs 132a, 132b and 132c defined by the solid length and the free length of the springs 132a, 132b and 132c may be about 17 inches to about 25 inches. By changing the compression of one or more of the springs, such as the inner springs 132b (also referred to as the center springs), the load on all of the axles I18a, 11 8b and 11 8c is redistributed. For example, if the length of the inner springs 132b is increased by about 1.5 inches, approximately 40,000 lbf is transferred about equally from the inner axle 118b (also referred to as the center axle) to the outer axles I18a and 118c. Thus, the inner axle l18b supports a load of 30,000 lbf, while each of the outer axles 118a and 118c, to which the extra load of 40,000 lbf has been redistributed about equally, now supports 90,000 lbf each, thereby increasing the traction of the wheels 112 (shown in Figures 1 and 2) of the outer axles 11 8a and 118c. 12 WO 2012/027520 PCT/US2011/049033 [0047] The pneumatic actuation system 150 or the electromechanical actuation system 1150 may be implemented in different configurations and arrangements. In some embodiments, the pneumatic actuation system 150 or the electromechanical actuation system 1150 converts rotational movement into translational or linear movement to change the preloading of springs to redistribute the load among the axles 118. It should be noted that other actuation methods may be used. For example, the actuator may be one or more of a linear actuator, a hydraulic actuator, an electric actuator, an electro magnetic actuator, a high pressure gas actuator, a mechanical actuator, and the like, that provides spring seat displacement. [0048] In general, the various embodiments provide spring seat displacement using the pneumatic actuation system 150 (shown in Figure 3) or the electromechanical actuation system 1150 (shown in Figure 13). For example, the pneumatic actuation system 150 or the electromechanical actuation system 1150 may cause movement, such as vertical movement of the spring seat 138, which may be located at a top or bottom of the springs 132. With respect to the pneumatic actuation system 150 illustrated in Figures 5 through 8, the moveable end of the spring 132 is the upper end with the lower end of the spring 132 being fixed, for example, supported by the axle box 134. For example, the pneumatic actuation system 150 may include an actuator 170 that operates using an upper compression mechanism to change the length of the springs 132. In this embodiment, the actuator 170 is shown mounted to the truck frame 160. However, in other embodiments, the actuator 170 may be mounted to other portions of the locomotive or locations of the truck frame 160. In various embodiments, the actuator 170 is only mounted to one of the axles 118, in particular the inner axles 11 8b (shown in Figures 1 and 2). However, the actuator 170 may be provided on different axles, for example, each of the outer axles 118a and 118c may include the actuator 170 and the inner axle 118b does not include an actuator 170. 13 WO 2012/027520 PCT/US2011/049033 [0049] In various embodiments, the actuator 170 includes a rotating cam arrangement having a cam 172 (shown more clearly in Figures 6 and 8) coupled to a lever 174 via a camshaft 176. For example, the camshaft 176 may be a rod extending from or through the cam 172 to the lever 174. The cam 172 and lever 174 are in substantially parallel planes with the camshaft 176 extending transverse or perpendicular therebetween. The camshaft 176 in the illustrated embodiment extends through an opening in the truck frame 160 to maintain the position of and support the camshaft 176. The camshaft 176 is coupled to one end of the cam 172 and to a center or middle region of the lever 174. [0050] Thus, movement of the lever 174, and more particularly rotation of the lever 174, is translated to and causes rotation of the cam 172. The rotation of the cam 172 causes translational or linear movement of the spring seat 138, which in this embodiment, is provided as a top plate 178 (e.g., a metal planar plate). The translational or linear movement compresses or releases compression of the springs 132. It should be noted that the top plate 178 acts as the spring seat for two springs 132 in this embodiment. However, separate top plates 178 may be provided for each of the springs 132. [0051] The lever 174 is actuated pneumatically, which in the illustrated embodiment includes a pneumatic cylinder 180 connected by a pin-slot mechanism to opposite ends of the lever 174. For example, the pneumatic cylinders 180 may be connected to each end of the lever 174 using. If the arrangement pivots, then the piston rod of the pneumatic cylinder 180 includes a flexible member (not shown) and is connected using, for example, a pin or other suitable fastener. The pneumatic cylinders 180 operate using the principles of pneumatics and may be any type of pneumatically operated cylinders. The pneumatic cylinders 180 (sometimes known as air cylinders) may be any mechanical devices that produce force, in combination with movement, and are powered by compressed gas (e.g., air). In some embodiments, the pneumatic 14 WO 2012/027520 PCT/US2011/049033 cylinders 180 are pneumatic braking cylinders also used in connection with brakes to stop the locomotive (shown in Figure 2). [0052] The pneumatic cylinders 180 are configured such that actuation of the pneumatic cylinders 180 causes rotation of the lever 174, which may be either clockwise or counterclockwise rotation. A stopper 182 is also provided on one end of the lever 174 to limit the rotational movement of the lever 174 in one direction, thereby limiting rotational movement of the cam 172. A stopper 184 is also provided on one end of the cam 172 to limit rotational movement of the lever 174, in another direction, for example, opposite the direction of the movement that is limited by the stopper 182. The stopper 184 is located on an end of the cam 172 opposite the end coupled to the camshaft 176. Thus, the stoppers 182 and 184 define the extent of rotation of the cam 172, which defines the amount of movement of the top plate 178, thereby defining the amount the springs 132 may be compressed. [0053] A guide 186, illustrated as a pin extending through the top plate 178, is provided to allow translational or linear movement of the top plate 178, while reducing or limiting out of plane movement. For example, during operation, the guide 186 guides the movement of the top late 178. [0054] It should be noted that the length, size and/or shape of the cam 172 and lever 174 may be varied. For example, the dimensions of the cam 172 and lever 174 may be selected based on an amount of mechanical advantage and/or an amount of compression of the springs 132 desired or required. [0055] Thus, as illustrated in Figures 7 and 8, as the cam 172 is rotated by the rotation of the lever 174, which is actuated by the pneumatic cylinders 180, the top plate 178 is moved. For example, as the cam 172 rotates, the rotational movement is translated to linear movement of the top plate 178, such that the top plate 178 is moved up or down (as viewed in Figures 7 and 8). The movement of the top plate 178 causes the springs 15 WO 2012/027520 PCT/US2011/049033 132 to compress or decompress. In Figures 7 and 8, the springs 132 are shown in a normal operating state and a weight redistribution state, respectively. In particular, in Figure 7, the cam 172 is in a 90 degree position with a flat end of the cam 172 engaging the top plate 178. In this normal operating state, the springs 132 are compressed by the top plate 178 such that all of the springs 132 of the locomotive suspension have the same compression, namely, the same preloading. For example, the springs 132 are compressed a same amount as other pre-compressed springs that do not include variable preloading. In some embodiments, the illustrated springs 132 having the variable compression are provided in connection with the suspension for the center axle 11 8b (shown in Figures 1 and 2), which are compressed a same amount as pre-compressed springs provided in connection with the suspension for the other axles of the locomotive truck, namely the outer axles 118a and 118 (shown in Figures 1 and 2). Thus, in the normal operating state, the load is distributed equally on each of the axles 118a-c. [0056] The cam 172 is then rotated, for example, in a counterclockwise direction (e.g., ninety degrees to a zero degree position) to the weight redistribution state as described herein. In this state, the top plate 178 is moved linearly upward such that the preloading is decreased as the compression on the springs 132 is decreased, which increases the working length of the springs 132. The amount of rotation may be limited, for example, by the stopper 184. In this weight redistribution state, because the length of the springs 132 has increased, some of the load on the springs 132 is redistributed to other springs as described herein. Accordingly, weight from the load is redistributed to other axles to provide dynamic weight management. [0057] The cam 172 may then be rotated, for example, in a clockwise direction to return to the normal operating state. The amount of rotation in this direction may be limited, for example, by the stopper 182. It should be noted that the stoppers 182 and 184 are provided to limit the rotation of the cam 172 between two maximum rotation points. 16 WO 2012/027520 PCT/US2011/049033 However, the cam 172 can be rotated to angle between these points to obtain a desired or required amount of weight transfer, and thereby traction. [0058] In various embodiments, the variable spring management is provided in connection with a center axle 118b as illustrated in Figures 9 through 11. As shown therein, the actuator 170 is mounted to an outside of the truck frame 160. However, it should be appreciated that one or more of the components may be mounted within the truck frame 160. In some embodiment, a mounting plate 190 is coupled to the camshaft 176. The mounting plate 190 secures the components of the variable spring management system to the truck frame 160, for example, by any suitable fastening means, such as using bolts or by welding. [0059] It should be noted that traction motors (not shown) in various embodiments, are not provided in connection with the center axle 11 8b, but are provided in connection with the outer axles 118a and 118c as described herein. It also should be appreciated that the truck frame 160 may be provided in any suitable manner to support and move a locomotive such that the variable spring preloading of various embodiments may be implemented in connection therewith. [0060] With respect to the electromechanical actuator system 1150 shown in Figures 13 through 17, the actuator 1170 includes a gearing arrangement 1172, illustrated as a gear pair having a pinion 1174 and a gear 1176 as shown more clearly in Figure 15. The pinion 1174 and gear 1176 are illustrated as toothed wheels, however, other types of gearing arrangements and components may be provided. For example, a sprocket or pulley arrangement may alternatively be provided. In the illustrated embodiment, the gearing arrangement 1172 is a step-down arrangement such that an increased mechanical advantage is provided. Accordingly, the pinion 1174, which is coupled to a motor 1178 via a motor shaft 1180 (or other coupling device), has a smaller diameter than the gear 1176, which is coupled to a power screw 1182. The motor 1178 is mounted to the axle 17 WO 2012/027520 PCT/US2011/049033 box 134 using a fastener 1183, for example, a clamp or clip. It should be noted that various components in Figure 14 are shown as transparent merely to illustrate the other components of the actuator 1170. [0061] As illustrated in Figures 16 and 17, the power screw 1182 extends through the axle box 134, such as through a threaded opening and having a spring cap 1184 mounted thereon. The spring cap 1184 is adapted to receive a lower end of the spring 132 such that rotation of the power screw 1182 causes linear movement of the spring cap 1184, thereby moving the spring 132 linearly, namely translating the spring 132. It should be noted that the spring cap 1184 may be any device capable of engaging or supporting the spring 132 to allow movement of the spring 132 to shorten or lengthen the spring 132. The illustrated spring cap 1184 includes an insert 1186 having a flange 1188 extending radially outward from the insert 1186. The insert 1186 is configured to be received within the spring 132 as shown in Figures 14 and 16. A non-moving spring seat 1190 is also provided on the top end of the spring 132 to prevent movement of the top end, such that the length of the spring 132 is changed by moving the spring seat 132 at the bottom end of the spring 132. Alternatively, if the location of the non-moving spring seat 1190 and spring seat 138 are switched, the upper end of the spring 132 moves with the bottom end fixed. [0062] In operation, the motor shaft 1180 is driven by the motor 1178, which may be an electric motor, and causes rotation of the pinion 1174. The rotation of the pinion 1174 causes rotation of the gear 1176, thereby rotating the power screw 1182. It should be noted that the power screw 1182 may be any type of screw capable of being driven by a motor and/or gearing arrangement such that rotational motion is converted to translational or linear motion. Thus, as the power screw 1182 rotates, the spring cap 1184 is moved upward or downward, thereby causing movement of the spring 132 that is positioned between the spring cap 1184 and the non-moving spring seat 1190. Accordingly, rotational movement of the power screw 1182 causes translational 18 WO 2012/027520 PCT/US2011/049033 movement of the spring cap 1184 to change the length of the spring 132 as described in more detail herein. [0063] As another example, which is illustrated in Figures 18 through 21, the moveable end of the spring 132 is the upper end with the lower end of the spring 132 being fixed. In particular, as shown in Figures 18 through 20, an actuator 2200 is mounted within the truck frame 160 (shown in Figure 11). In some embodiments, the actuator 2200 is coupled to an axle 118 of a vehicle having a pair of wheels 112. The actuator 2200 is mounted within an opening in a middle portion of the truck frame 160, namely in connection with a center or inner axle 11 8b between outer axles I18a and 11 8c (all shown in Figures 1 and 2). In this embodiment, a traction motor 110 (shown in Figures 1 and 2) is coupled to each of the outer axles 118a and 118c, but not the inner axle 118b having the actuator 2200. The traction motors 110 drive the vehicle as described in more detail herein, which may be coupled to the axles 118a and 118c with gearing arrangements. It should be appreciated that the truck frame 160 may be provided in any suitable manner to support and move a locomotive such that the variable spring preloading of various embodiments may be implemented in connection therewith. [0064] In general, and as shown in Figure 18, the actuator 2200 includes a motor 2206 that drives a power screw 2208, causing movement of an actuating beam 2210 (e.g., an actuating arm) via a gear 2212 engaged with a pinion 2228 mounted on a motor shaft 2226. The actuating beam 2210 causes linear movement of the spring 132 to change a length of the spring 132. It should be noted that for simplicity and ease of illustration the actuator 2200 is shown coupled to only one spring 132 of the four springs connected to the axle 118. The actuator 2200, however, is configured to change a length and preloading of all of the four springs 132. Thus, the described components for changing a length of one spring 132 may be used to change a length of any of the springs 132, for example, using four actuating beams 2210. 19 WO 2012/027520 PCT/US2011/049033 [0065] As illustrated more clearly in Figures 18 through 21, the actuating beam 2210 is connected to a guide and stopper arrangement 2216, which is coupled to a plunger 2218 having a spring seat 2220 engaging a top of the spring 132 as described in more detail herein. The bottom of the spring 132 is supported by the axle box 134. It should be noted that additional support members 2224 may be provided to support one or more of the components of the actuator 2200 in the opening 2204. In this embodiment, the support members 2224 are configured as additional bridge supports. [0066] In operation, and referring to Figures 18 through 21, the motor 2206 drives the gear 2212 using a pinion 2228 that is smaller in diameter than the gear 2212. The rotation of the motor shaft 2226, and more particularly, rotation of the shaft with a spline 2230 (e.g., ball spline) connected to the pinion 2228 via the gear 2212, results in axial vertical motion of the shaft 2214 as a result of the movement of the threads 2232 at the end of the power screw 2208, which are at the end of the shaft 2214. The shaft 2214, which may be a spline shaft, includes a collar 2234 (which connects to the actuating beam 2210, two of which are shown in Figure 20) at one end and the lower end of the power screw 2208 at the other end of the shaft 2214, engages a spring mounting platform 2236. [0067] The rotation of the power screw 2208 illustrated by the arrow RI causes rotation of the gear 2212 (caused by the motor 2206 and pinion 2228) and vertical motion of the shaft 2214 illustrated by the arrow V. The vertical motion of the shaft 2214 actuates the actuating beam 2210, and in particular, causes pivoting motion of the actuating beam 2210. The pivoting actuating beam 2210 causes the plunger 2218 to move, for example, push or pull, such that the spring 132 is compressed or released. Once the desired or required actuation is complete, such as compressing or releasing the spring to decrease or increase, respectively, the length of the spring 132, the plunger 2218 may be locked in position using any suitable locking mechanism. It should be noted that one or more thrust bearings 2240 may be provided in connection with the gear 2212. 20 WO 2012/027520 PCT/US2011/049033 [0068] Thus, the threads 2232 on the end of the shaft 2214 (forming the power screw 2208) mates with threads on the frame structure, illustrated as the support member 2224. Rotation of the power screw 2208 results in linear motion of the shaft 2214 relative to the truck frame 160, thereby varying the relative position of the spring 132 to the mounting platform 2236. Accordingly, the power screw 2208 translates or converts rotational movement into linear or translational movement. Thus, linear movement of the collar 2234 causes the springs 132 to move up or down via pivot points 2242. For example, as illustrated in Figure 21, vertical guiding and locking may be provided such that the actuating beam 2210 engages within a slot 2250 having stoppers 2252 (e.g., rubber blocks) at opposite ends of the slot 2250 to limit the movement of the actuating beam 2210. As the actuating beam 2210 rotates, the slot 2250 maintains the vertical motion of the end of the actuating beam 2210 along one axis, which motion is limited when a bolt 2254 within a slot 2256 of the actuating beam 2210 contacts one of the stoppers 2252. [0069] It should be noted that in the various embodiments, the gears are mounted using bearings (e.g., thrust or ball bearings), which are not necessarily illustrated in the Figures. [0070] Thus, various embodiments provide variable spring preloading of a locomotive suspension system. The variable spring preloading causes load redistribution among the axles of the locomotive. For example, dynamic weight transfer may be provided from a center axle to outer axles in a locomotive truck. [0071] A method 200 as shown in Figure 12 also may be provided to dynamically redistribute weight in a vehicle. The method 200 includes configuring springs of a vehicle suspension for variable preloading at 202. For example, a mechanism for lengthening and shortening the springs, such as using a spring seat displacement with pneumatic or electromechanical actuation described herein allows for 21 WO 2012/027520 PCT/US2011/049033 variable preloading of the springs based on a variable compression applied by the spring seat. [0072] The method 200 then includes mounting the preloading mechanism to the vehicle at 204. For example, springs having the preloading mechanism may be mounted to the vehicle or a portion thereof, such as the axle box. In some embodiments, the preloading mechanism is provided on springs of an inner axle and not on the outer axles of a three axle truck, with two trucks provided per vehicle. [0073] With the preloading mechanism mounted with the springs, the length of the springs is controlled at 206 to provide variable preloading and load/weight redistribution among the axles of the vehicle. For example, by varying the length of one or more of the springs, the preloading of the spring is changed, which redistributes the load among the axles of the vehicle. The controlling may be provided using a control module that dynamically adjusts the length of the springs using an actuator, for example, a pneumatic actuator or an electromechanical actuator. The changes to the preloading may be based on different factors, such as traction limited modes of operation. [0074] Various embodiments may dynamically control preloading of springs in a vehicle. For example, variable spring preloading may be provided on the center axle suspension (spring) pocket on the two trucks in a vehicle. In one embodiment, the spring pocket is translated vertically within the axle box. A counter sunk cavity may replace the spring seat on the axle box. Alternatively, the spring pocket may translate on the truck side as well. The translation is affected by a power screw driven by a motorized drive through an appropriate gear reduction. With the translation of spring pocket, the effective preload on the spring can be varied. This varied preloading results in changing the overall load distribution on the three axles of the truck, leading to a distribution of the vehicle load to put more load on the powered outer axles. The higher load on the powered outer axles helps improve traction. In some embodiments, the redistribution of 22 WO 2012/027520 PCT/US2011/049033 load, which reduces wheel slip, also increases braking. For example, the weight transfer prevents the wheels from slipping, thereby providing an anti-locking braking system for a vehicle. Such anti-locking braking system may be used, for example, at high speed operation and can reduce braking time. [0075] In one embodiment, a counter sunk cavity may be machined in the axle box. The spring seat is mounted on a power screw that is mounted in this cavity in the axle box. The power screw is rotated with a geared motorized drive. The rotary motion is, thus, converted into translatory motion for the power screw, which in turn drives the spring seat and accordingly the spring up or down. The rotational motion can be controlled to provide the adequate translation for the spring seat. [0076] Alternatively the spring may be configured to translate on the truck side with a similar mechanism. A single power screw with a motorized drive can be employed to translate all the four spring seats simultaneously through a lever mechanism. [0077] In operation, and for example, the variable preloading redistributes the load on the three axles of a truck in a vehicle. The redistribution provides more load on the powered axles and may be used, for example, in locomotives that have six load carrying axles, but has traction motors on only four axles (the outer ones for each truck). The load redistribution enables more traction to be generated on the powered axles, such as during traction limited modes of operation for these locomotives. Thus, the locomotive may be driven with four traction motors. [0078] The various embodiments may be implemented with no changes to the truck frame. For example, the motor and the variable spring preload mechanism can be mounted on the truck frame on either the inside or outside of the frame. [0079] In one embodiment, a vehicle suspension system is provided. The vehicle suspension system includes a plurality of springs, a plurality of moveable spring 23 WO 2012/027520 PCT/US2011/049033 seats, an actuator, and a controller. The moveable spring seats are configured to adjust a length of the plurality of springs, e.g., the spring seats can be moved, and are configured, when so moved, to adjust the length of the springs. The actuator is connected to the plurality of moveable spring seats and is configured to move the moveable spring seats to adjust the length of the plurality of springs. The controller is coupled to the actuator to control the actuator to adjust the length of the plurality of springs. [0080] In another aspect, the controller dynamically adjusts the length of the plurality of springs based on operating conditions. [0081] In another aspect, the moveable spring seats are positioned at one end of the plurality of springs with an opposite end of the plurality of springs being fixed. [0082] In another aspect, the vehicle suspension system also includes an axle box. One end of the plurality of springs engages the plurality of moveable spring seats and an opposite end engages a vehicle frame in a non-moveable configuration. [0083] In another aspect, the plurality of springs comprises outer axle springs and inner axle springs and the plurality of moveable spring seats is coupled only to the inner axle springs. [0084] In another aspect, the plurality of moveable spring seats is configured for vertical linear movement. [0085] In another aspect, the plurality of moveable spring seats comprises moveable plates. [0086] In another aspect, the actuator is a pneumatic actuator. [0087] In another aspect, the pneumatic actuator comprises a cam arrangement configured to convert rotational movement of a lever actuated by cylinders to 24 WO 2012/027520 PCT/US2011/049033 translational movement of the plurality of spring seats to linearly adjust a length of the plurality of springs. [0088] In another aspect, the pneumatic actuator comprises a lever configured to rotate a camshaft using a pair of cylinders pivotally connected to the lever. Rotation of the camshaft rotates a cam that translates the plurality of moveable spring seats. [0089] In another aspect, the plurality of moveable spring seats comprises plates and the vehicle suspension system also includes a guide that is configured to maintain the plurality of moveable spring seats along a linear path. [0090] In another aspect, the vehicle suspension system also includes a pair of stops connected to the lever and the cam to define a total amount of rotation of the cam. [0091] In another aspect, the cam is configured to rotate about 90 degrees. [0092] In another aspect, the actuator is an electromechanical actuator. [0093] In another aspect, the electromechanical actuator comprises a geared motor. The electromechanical actuator converts rotational movement of the geared motor to translational movement of the plurality of spring seats to linearly adjust a length of the plurality of springs. [0094] In another aspect, the electromechanical actuator comprises power screws configured to translate the plurality of moveable spring seats. [0095] In another aspect, the vehicle suspension system also includes a spring cap coupled to the power screws and forming the moveable spring seats. [0096] In another aspect, the electromechanical actuator comprises a geared motor connected to the plurality of moveable spring seats with actuating beams. The pivoting movement of the actuating beams translates the moveable spring seats. 25 WO 2012/027520 PCT/US2011/049033 [0097] In another aspect, the electromechanical actuator further comprises a power screw that converts rotational movement of the geared motor to translational movement of the plurality of moveable spring seats to linearly adjust a length of the plurality of springs. [0098] In another aspect, the vehicle suspension system also includes a plunger connecting the plurality of spring seats to the plurality of actuating beams. [0099] In another aspect, the pivoting movement one of pushes and pulls the plunger. [00100] In another aspect, the electromechanical actuator further comprises a guiding slot with end stops to maintain the plurality of moveable spring seats along a linear path between the end stops. [00101] In another embodiment, a vehicle system is provided. The vehicle system includes a frame, a traction motor, a plurality of moveable spring seats, an actuator, and a controller. The frame is configured to receive a plurality of axles. Each of the axles has a corresponding spring suspension system with a plurality of springs. The traction motor is coupled to at least some of the plurality of axles. The moveable spring seats are configured to adjust a length of the plurality of springs to change a preloading of the springs. The actuator is connected to the plurality of moveable springs and is configured to move the moveable spring seats to adjust the length of the plurality of springs. The controller is coupled to the actuator to control the actuator to adjust the length of the plurality of springs. [00102] In another aspect, the controller dynamically adjusts the length of the plurality of springs based on operating conditions. [00103] In another aspect, the actuator is a pneumatic actuator. 26 WO 2012/027520 PCT/US2011/049033 [00104] In another aspect, the traction motors are coupled only to outer axles and the pneumatic actuator is coupled to an outside of the frame in connection with a center axle. [00105] In another aspect, the pneumatic actuator comprises a cam arrangement configured to translate rotational movement of a lever actuated by a pair of cylinders to linear movement of the plurality of moveable spring seats. [00106] In another aspect, the vehicle system also includes a pair of stops connected to the lever and a cam of the cam arrangement to define a total amount of rotation of the cam. [00107] In another aspect, the pneumatic actuator comprises cylinders further configured to operate a braking operation. [00108] In another aspect, the actuator is an electromechanical actuator. [00109] In another aspect, the traction motors are coupled only to outer axles and the electromechanical actuator is coupled within an opening inside of the frame in connection with a center axle. [00110] In another aspect, the electromechanical actuator is coupled to an outside of the frame to an axle box. [00111] In another aspect, the electromechanical actuator comprises a geared electric motor and rotational movement of the geared electrical motor is translated to linear movement of the moveable spring seats. [00112] In another embodiment, a method for dynamically redistributing weight in a vehicle is provided. The method includes configuring a plurality of springs of a vehicle suspension system for variable preloading, mounting a preloading mechanism 27 WO 2012/027520 PCT/US2011/049033 with the plurality of springs to the vehicle, the preloading mechanism having an actuator, and controlling a length of the plurality of springs to provide variable spring preloading and load redistribution among axles of the vehicle. [00113] In another aspect, the method also includes controlling the spring length based on operating conditions using a control module. [00114] In another aspect, the method also includes controlling the length of the springs in a center suspension connected to a center axle not having a traction motor. The outer suspensions that are connected to outer axles include traction motors. [00115] In another aspect, the actuator is a pneumatic actuator. [00116] In another aspect, the actuator is an electromechanical actuator. [00117] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the disclosed subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to one of ordinary skill in the art upon reviewing the above description. The scope of the subject matter described herein should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 28 [00118] This written description uses examples to disclose several embodiments of the above subject matter, including the best mode, and also to enable any person skilled in the art to practice the embodiments of subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. [00119] Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereof. 29

Claims

1. A vehicle suspension system, comprising: a plurality of springs; a plurality of moveable spring seats configured to adjust a length of the plurality of springs; a pneumatic actuator connected to the plurality of moveable spring seats and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the plurality of springs comprise outer axle springs and inner axle springs, and wherein the plurality of movable spring seats are coupled only to the inner axle springs.

2. The vehicle suspension system of claim 1, wherein the controller dynamically adjusts the length of the plurality of springs based on operating conditions.

3. The vehicle suspension system of claim 1 or 2, wherein the moveable spring seats are positioned at one end of the plurality of springs with an opposite end of the plurality of springs being fixed.

4. The vehicle suspension system of any one of claims 1 to 3, wherein the pneumatic actuator comprises a cam arrangement configured to convert rotational movement of a lever actuated by cylinders to translational movement of the plurality of spring seats to linearly adjust a length of the plurality of springs. 30

5. The vehicle suspension system of any one of claims 1 to 4, further comprising an axle box and wherein one end of the plurality of springs engages the plurality of moveable spring seats and an opposite end engages a vehicle frame in a non moveable configuration.

6. The vehicle suspension system of claim 1 to 5, wherein the plurality of moveable spring seats is configured for vertical linear movement.

7. The vehicle suspension system of any one of claims 1 to 6, wherein the plurality of moveable spring seats comprises moveable plates.

8. The vehicle suspension system of any one of claims 1 to 7, wherein the pneumatic actuator comprises a lever configured to rotate a camshaft using a pair of cylinders pivotally connected to the lever, wherein rotation of the camshaft rotates a cam that translates the plurality of moveable spring seats.

9. The vehicle suspension system of claim 8, wherein the plurality of moveable spring seats comprises plates and further comprising a guide configured to maintain the plurality of moveable spring seats along a linear path.

10. The vehicle suspension system of claim 8 or 9, further comprising a pair of stops connected to the lever and the cam to define a total amount of rotation of the cam. 31

11. The vehicle suspension system of anyone of claims 8 to 10, wherein the cam is configured to rotate about 90 degrees.

12. A vehicle system, comprising: a frame configured to receive a plurality of axles, each of the axles having a corresponding spring suspension system with a plurality of springs; a traction motor coupled to at least some of the plurality of axles; a plurality of moveable spring seats configured to adjust a length of the plurality of springs to change a preloading of the springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the traction motors are coupled only to outer axles and the pneumatic actuator is coupled to an outside of the frame in connection with a center axle.

13. The vehicle system of claim 12, wherein the controller dynamically adjusts the length of the plurality of springs based on operating conditions.

14. The vehicle system of claim 12 or 13, wherein the pneumatic actuator comprises a cam arrangement configured to translate rotational movement of a lever actuated by a pair of cylinders to linear movement of the plurality of moveable spring seats. 32

15. The vehicle system of claim 14, further comprising a pair of stops connected to the lever and a cam of the cam arrangement to define a total amount of rotation of the cam.

16. The vehicle system of anyone of claims 12 to 15, wherein the pneumatic actuator comprises cylinders further configured to operate a braking operation.

17. A method for dynamically redistributing weight in a vehicle, the method comprising: configuring a plurality of springs of a vehicle suspension system for variable preloading; mounting a preloading mechanism with the plurality of springs to the vehicle, the preloading mechanism having a pneumatic actuator; and controlling a length of the plurality of springs to provide variable spring preloading and load redistribution among axles of the vehicle; and controlling the length of the springs in a center suspension connected to a center axle not having a traction motor and wherein outer suspensions connected to outer axles include traction motors.

18. The method of claim 17, further comprising controlling the spring length based on operating conditions using a control module.

19. A vehicle suspension system, comprising: a plurality of springs; 33 a plurality of moveable spring seats configured to adjust a length of the plurality of springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the pneumatic actuator comprises a lever configured to rotate a camshaft using a pair of cylinders pivotally connected to the lever, wherein rotation of the camshaft rotates a cam that translate the plurality of moveable spring seats.

20. The vehicle suspension system of claim 19, wherein the plurality of moveable spring seats comprises plates and further comprising a guide configured to maintain the plurality of moveable spring seats along a linear path.

21. The vehicle suspension system of claim 19 or 20, further comprising a pair of stops connected to the level and the cam to define a total amount of rotation of the cam.

22. The vehicle suspension system of anyone of claims 19 to 21, wherein the cam is configured to rotate about 90 degrees.

23. A vehicle system, comprising: 34 a frame configured to receive a plurality of axles, each of a frame configured to receive a plurality of axles, each of the axles having a corresponding spring suspension system with a plurality of springs; a traction motor coupled to at least some of the plurality of axles; a plurality of moveable spring seats configured to adjust a length of the plurality of springs to change a preloading of the springs; a pneumatic actuator connected to the plurality of moveable springs and configured to move the moveable spring seats to adjust the length of the plurality of springs; and a controller coupled to the pneumatic actuator to control the pneumatic actuator to adjust the length of the plurality of springs, wherein the pneumatic actuator comprises a cam arrangement configured to translate rotational movement of a level actuated by a pair of cylinders to linear movement of the plurality of moveable spring seats.

24. The vehicle system of claim 23, further comprising a pair of stops connected to the level and a cam of the cam arrangement to define a total amount of rotation of the cam. 35