A LOCOMOTIVE SERVICE MANAGEMENT SYSTEM AND METHOD THEREOF

BACKGROUND

[0001] A locomotive typically includes two trucks. Typically, a truck supports the weight of a locomotive, and generally includes a propulsion subsystem, a suspension subsystem, and a braking subsystem. Fig. 1 shows a perspective view of a typical truck 10 of a locomotive (not shown). Along with other components not discussed with reference to Fig. 1, a truck typically includes a plurality of pairs of wheels mounted on respective axles. The wheels are generally flanged wheels due to a flange protruding out from one side of the wheels. For example, in Fig. 1 a first pair of wheels 12 is mounted on a first spaced axle 18; a second pair of wheels 14 is mounted on a second spaced axle 20; and a third pair of wheels 16 is mounted on a third spaced axle 22. While Fig. 1 shows the three pairs of the wheels 12, 14, 16, a truck may have less or more number of pairs of wheels. The ends of the axles 18, 20, 22 are rotatably received in pairs of journal boxes 24, 26, 28, respectively. Particularly, the ends of the first axle 18 are rotatably received by the first pair the journal box 24; the ends of the second axle 20 are rotatably received by the second pair of the journal box 26, and the ends of the third axle 22 are rotatably received by the third pair of journal box 28. Due to the perspective view, one wheel is visible in each of the pairs of the wheels 12, 14, 16, and one journal box is visible in each of the pairs of journal boxes 24, 26, 28. Typically, the pairs of wheels 12, 14, 16 in the truck 10 are defined by certain measurements.

[0002] Generally each wheel in the pairs of wheels 12, 14, 16 includes a rim and a flange. Furthermore, each wheel in the pairs of wheels 12, 14, 16 may be defined by a plurality of measurements or a specification. The specification, for example, includes a rim thickness, a flange thickness, a flange height, and a reference groove reading. Fig. 2A shows a front view 200 of a wheel 203 to show various measurements that define a wheel 203, and Fig. 2B shows a cross-sectional view 201 of a portion of the wheel 203 referred to in Fig. 2(a) to show various measurements that define the wheel 203. The wheel 203 includes a flange 205 and a rim 207. The flange 205 comprises a flange height 204, and a flange thickness 202. Furthermore, as shown in Fig. 2(b), the rim 207 comprises a rim thickness 206, and a reference groove reading 208.

[0003] Typically, specifications of wheels of locomotives are required to meet certain specification requirements of customers, and an authority, such as, a railway authority, such as, Federal Railway Administration (FRA). Therefore, commissioned locomotives meet the specification requirements of customers, and the authority. However during operation of the locomotives, the wheels may undergo certain wear and tear, and such wear and tear may change the specification of the wheels. Due to the wear and tear of the wheels, the wheels may not meet the specification requirements of customers, and the authority. Therefore, locomotives are generally sent for servicing and maintenance at regular intervals. During the maintenance of the locomotives, multiple checks are carried out to identify whether one or more of the wheels does not meet the specification requirements. Based on the checks, typically wheel tru operators take decisions as to whether one or more of the wheels of the locomotives need to be trued, replaced, shimmed or scrapped. Such decisions are taken by the wheel tru operators, and therefore the cost effectiveness of these decisions is dependent on human intelligence. The probability of errors in such decisions is higher. Accordingly, automated methods and systems that take optimal decisions during servicing and maintenance of locomotives are required.

BRIEF DESCRIPTION

[0004] A locomotive service management system is presented. The locomotive comprises a processing subsystem that generates a recommendation by minimizing an objective function by satisfying a plurality of constraints formulated based upon at least one of a plurality of locomotive input wheel measurements corresponding to locomotive wheels mounted on respective locomotive axles in one or more trucks of a locomotive, a plurality of inventory input wheel measurements corresponding to inventory wheels mounted on respective inventory axles, a plurality of measurement thresholds, a plurality of tolerances, a look up table, and a plurality of decision variables, wherein the objective function comprises at least one of: the plurality of decision variables corresponding to one or more activities and associated costs for implementing the one or more activities on at least one of the locomotive wheels, the respective locomotive axles, the inventory wheels, and the respective inventory axles.

DRAWINGS

[0005] These and other features and aspects of embodiments of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0006] Fig. 1 shows a perspective view of a typical truck of a locomotive;

[0007] Fig. 2A shows a front view of a wheel to show various measurements that define a wheel;

[0008] Fig. 2B shows a cross-sectional view of a portion of the wheel referred to in Fig. 2(a) to show various measurements that define the wheel; and

[0009] Figure 3 is a block diagram of a locomotive service management system, in accordance with one embodiment of the present systems.

DETAILED DESCRIPTION

[0010] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet further embodiments. It is intended that the present disclosure includes such modifications and variations.

[0011] As used herein, the term "wheel measurements" refers to dimensions of a wheel of a locomotive. As used herein, the term "locomotive input wheel measurements" is used to refer to: wheel measurements of wheels of a locomotive that has arrived for maintenance; or wheel measurements that are required to be assessed to determine whether one or more of specified railway authority requirements, safety requirements, and/or customer requirements are not complied with. As used herein, the term "inventory input wheel measurements" is used to refer to: wheel measurements of inventory wheels mounted on an inventory axle that is available to replace a locomotive axle. As used herein, the term "violation" refers to existence of a contravention in a wheel, an axle, a truck, or a locomotive because one or more of specified railway authority requirements, safety requirements, and/or customer requirements are not complied with.

As used herein, the term "wheel level violation" refers to existence of a violation in a wheel because one or more wheel measurements of the wheel in a locomotive or an inventory wheel does not satisfy respective measurement threshold. As used herein, the term "axle level violation" refers to existence of violations in an axle because a difference, between a wheel measurement of a wheel mounted on the said axle in a locomotive and the wheel measurement of another wheel mounted on the said axle in the said locomotive, does not fall within an axle level tolerance. As used herein, the term "truck level violation" refers to existence of a violation in two different axles when a difference of two same wheel measurements of two wheels mounted on the two different axles of a single truck is greater than a truck level tolerance. As used herein, the term "locomotive level violation" refers to existence of violations in two different axles when a difference of two same wheel measurements of two wheels mounted on the two different axles of two different trucks is greater than a locomotive level tolerance.

[0012] As used herein, the term "tolerance" refers to a range or a value determined based upon specified railway authority requirements, safety requirements, and/or customer requirements such that when wheel measurements of wheels in a locomotive or a quantity, determined based upon one or more of the wheel measurements of the wheels in the locomotive, falls within the range or the value then the railway authority requirements, the safety requirements, and/or the customer requirements are complied with. As used herein, the term "measurement threshold" refers to a maximum or minimum permissible value of a wheel measurement, wherein the maximum or minimum permissible value is determined based upon railway authority requirements, safety requirements, and/or customer requirements. As used herein, the term "look up table" refers to a table that maps a wheel measurement to a corresponding amount of reduction required in another wheel measurement, or maps the wheel measurement to another corresponding wheel measurement. As used herein, the term "reset values" refers to a wheel measurement value that may be equated to a wheel measurement of a wheel, when the wheel measurement of the wheel does not meet one or more of railway authority requirements, safety requirements, and/or customer requirements.

[0013] As used herein, the term "decision variable" is a variable corresponding to an activity that may be enabled when a decision is taken to implement the corresponding activity on an inventory wheel or a locomotive wheel, and the decision variable may be disabled when a decision is taken to not implement the activity on the inventory wheel or the locomotive wheel. As used herein, the term "wheel constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a wheel level violation exists in a locomotive wheel or an inventory wheel, and enable a decision variable to obviate the wheel level violation. As used herein, the term "wheels-within-axle constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether an axle level violation exists in a locomotive axle or an inventory axle, and enable a decision variable to obviate the axle level violation. As used herein, the term "wheels-within-truck constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a combination of axles, mounted on same truck or to be mounted on the same truck, have a truck level violation, and enable a decision variable to obviate the truck level violation; wherein the combination comprises a locomotive axle and another locomotive axle, a locomotive axle and an inventory axle, and an inventory axle and another inventory axle. As used herein, the term "wheels-across-trucks constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a first axle of a first truck and a second axle of a second truck have a locomotive level violation, and enable a decision variable to obviate the locomotive level violation; wherein the first axle and the second axle comprises a locomotive axle, an inventory axle, or combinations thereof.

[0014] The embodiments described herein relate to a locomotive service management system. The locomotive service management system generates recommendations. The recommendations may include one or more activities to be performed on wheels or axles of a locomotive while servicing or maintaining the locomotive. The activities, for example include truing a wheel, scrapping an axle, replacing an axle, shimming an axle, or the like. Furthermore, the locomotive service management system determines a number of wheel cuts required in the wheel while truing the wheel and a number of inches to be removed in each of the wheel cuts. Additionally, the locomotive service management system determines a cost that may be incurred by a user for implementing the recommendations.

[0015] Figure 3 is a block diagram of a locomotive service management system 300, in accordance with one embodiment of the present systems. In the embodiment of Fig. 1, the locomotive service management system 300 includes: a locomotive 302 that has arrived for maintenance to a servicing station (not shown), one or more users 304 for taking measurements of the locomotive 302, a storage device 306, and a processing subsystem 308 that generates recommendations 346. In one embodiment, the locomotive service management system 302 includes one or more inventory axles 303 that are available for replacement of one or more axles in the locomotive 302.

[0016] In the presently contemplated configuration, the locomotive 302 includes two trucks including a first truck 310 and a second truck 312. While the presently contemplated configuration shows two trucks 310, 312 in the locomotive 302, the locomotive 302 may have more or less than two trucks. In the presently contemplated configuration, each of the trucks 310, 312 includes three axles. For example, the first truck 310 includes a first truck first axle 314, a first truck second axle 316, and a first truck third axle 318. The axles 314, 316, 318 of the first truck 310 shall be collectively referred to by the reference numeral 325. Furthermore, axles of the second truck 312 shall be collectively referred to by the reference numeral 327. Furthermore, two wheels are mounted on each of: the axles 314, 316, 318, and the axles 327. For example, the first truck first axle 314 has a first wheel 320 and a second wheel 322. All wheels mounted on the axles 314, 316, 318 of the first truck 310 shall hereinafter be referred to by the reference numeral 324. Furthermore, all wheels mounted on the axles 327 of the second truck 312 shall hereinafter be referred to by the reference numeral 326.

[0017] Furthermore, in one embodiment, the locomotive service management system 302 includes one or more inventory axles 303 that are available for replacing one or more of the axles 325, 327. For differentiating the inventory axles 303 from the axles 314, 316, 318, 325, 327 in the locomotive 302, the axles 314, 316, 318, 325, 327' are interchangeably referred to as locomotive axles 314, 316, 318, 325, 327. Similarly, for differentiating the inventory wheels mounted on the inventory axles 303 from the wheels 324, 326, the wheels 324, 326 are interchangeably referred to as locomotive wheels 324, 326. Similarly, for differentiating the inventory wheels mounted on the inventory axles 303 from the first wheel 320, the phrase 'first wheel 320' is interchangeably referred to as 'first locomotive wheel 320'. Again, for differentiating the inventory wheels mounted on the inventory axles 303 from the second wheel 322, the phrase 'second wheel 322' is interchangeably referred to as 'second locomotive wheel 322'.

[0018] The user 304 takes measurements of one or more of the locomotive wheels 324, 326 in the locomotive 302 to generate locomotive input wheel measurements 328. The user 304 takes measurements of one or more of the inventory wheels mounted on the inventory axles 303 to generate inventory input wheel measurements 336. While in the presently contemplated configuration, the user 304 takes the measurements of the locomotive wheels 324, 326 and the inventory wheels, in certain embodiments, machines may take the measurements. As previously noted, the term "wheel measurements" refers to dimensions of a wheel of a locomotive. Additionally, as previously noted, the term "locomotive input wheel measurements" is used to refer to: wheel measurements of wheels of a locomotive that has arrived for maintenance; or wheel measurements that are required to be assessed to determine whether one or more of specified railway authority requirements, safety requirements, and/or customer requirements are not complied with. Furthermore, as previously noted, the term "inventory input wheel measurements" is used to refer to: wheel measurements of inventory wheels mounted on an inventory axle that is available to replace a locomotive axle.

[0019] In the embodiment of Fig. 3, the locomotive input wheel measurements 328 include a flange height, a flange thickness, a reference groove reading, and a rim thickness of the wheels 324, 326. Furthermore, in the embodiment of Fig. 3, the inventory input wheel measurements 336 include a flange height, a flange thickness, a reference groove reading, and a rim thickness of the inventory wheels mounted on the inventory axle 303. However, the locomotive input wheel measurements 328 and the inventory input wheel measurements 336 may include other measurements. The user 304 transmits or enters the locomotive input wheel measurements 328 to the processing subsystem 308. The processing subsystem 308, for example, may include a user interface (not shown) that interacts with the user 304 or a machine to receive the locomotive input wheels measurements 328. Furthermore, the processing subsystem 308 receives the inventory input wheels measurements 336.

[0020] The storage device 306 stores measurement thresholds 330, tolerances 332, a look up table 334, and the inventory input wheel measurements 336. As previously noted, the "measurement threshold" refers to a maximum or a minimum permissible value of a wheel measurement, wherein the maximum or minimum permissible value is determined based upon railway authority requirements, safety requirements, and/or customer requirements. In the embodiment of Fig. 3, the measurement thresholds 330 include a flange thickness threshold, a flange height threshold, a reference groove reading threshold, a rim thickness threshold, a maximum flange height threshold, a minimum flange thickness threshold, a minimum rim thickness threshold, a minimum reference grove threshold, or other thresholds corresponding to other wheel measurements or combinations thereof.

[0021] The storage device 306 further stores the tolerances 332. The tolerances 332, for example, may include an axle level tolerance, a truck level tolerance, and a locomotive level tolerance. In one embodiment, when the tolerances 332 correspond to a wheel measurement namely reference groove reading, the tolerances 332 may include a maximum reference groove axle level tolerance, a maximum reference groove truck level tolerance, and a maximum reference groove locomotive level tolerance.

[0022] Furthermore, the storage device 306 stores the look up table 334. As previously noted, the term "look up table" refers to a table that maps a wheel measurement to a corresponding amount of reduction required in another wheel measurement, or maps the wheel measurement to another corresponding wheel measurement. For example, the look up table 334 may map a flange thickness to a rim reduction of a wheel. For example, the look up table 354 may be used to determine an amount of rim reduction required in the first locomotive wheel 320 based on the flange thickness of the first locomotive wheel 320. Furthermore, the storage device 306 stores the inventory input wheel measurements 336 and reset values 339.

[0023] The processing subsystem 308 comprises an objective function 338 and a plurality of constraints 340. The processing subsystem 308 minimizes the objective function 338 by satisfying the constraints 340. Particularly, the processing subsystem 308 minimizes the objective function 338 by satisfying the constraints 340 to generate a recommendation 342. In one embodiment, the processing subsystem 308 minimizes the objective function 338 to minimize a total cost of implementing the recommendation 342 on at least one of the locomotive wheels 324, 326, the locomotive axles 325, 327, the inventory wheels, and the inventory axles 303. The recommendation 342 comprises one or more activities that may be performed or executed on one or more of the locomotive wheels 324, 326, the locomotive axles 325, 327, the inventory wheels, and the inventory axles 303 to obviate one or more wheel level violations, axle level violations, and truck level violations in the locomotive wheels 324, 326 and the locomotive axles 325, 327 of the locomotive 302. Particularly, the recommendation 342 comprises the activities that may be performed or executed on the locomotive wheels 324, 326, the locomotive axles 325, 327, the inventory wheels, and the inventory axles 303 to comply with one or more railway authority requirements, safety requirements, and/or customer requirements. The activities comprise a truing activity, a scrapping activity, a replacement activity, a shimming activity, or combinations thereof. The implementation of the recommendation 342 on the locomotive wheels 324, 326 and the inventory wheels obviates wheel level violation, an axle level violation, a truck level violation, and a locomotive level violation. Particularly, the execution of the activities in the recommendation 342 on the locomotive wheels 324, 326 and the inventory wheels obviates the wheel level violation, the axle level violation, the truck level violation, and the locomotive level violation.

[0024] The objective function 338 comprises at least one of: a plurality of decision variables corresponding to the activities, and associated costs for implementing the activities. The decision variables comprise a truing decision variable, a scrapping decision variable, a replacement decision variable, a shimming decision variable, an amount of rim reduction required decision variable, or combinations thereof. As used herein, the term "decision variable" is a variable corresponding to an activity that may be enabled when a decision is taken to implement the corresponding activity on an inventory wheel or a locomotive wheel, and the decision variable may be disabled when a decision is taken to not implement the corresponding activity on the inventory wheel or the locomotive wheel. The truing decision variable corresponds to the truing activity; the scrapping decision variable corresponds to the scrapping activity; the replacement decision variable corresponds to the replacement activity; the shimming decision variable corresponds to the shimming activity, the amount of rim reduction required decision variable corresponds to an amount of rim reduction required in a wheel.

In the embodiment of Fig. 3, the one or more of the decision variables are enabled by equating the decision variable equal to 1. Furthermore, in the embodiment of Fig. 3, the decision variable is disabled by equating the decision variable equal to 0. The amount of rim reduction required decision variable is enabled by extracting an amount of rim reduction from the look up table 334, and by equating the amount of rim reduction required decision variable to the amount of rim reduction extracted from the look up table 334. Furthermore, the amount of rim reduction required decision variable is disabled by equating the amount of rim reduction required decision variable equal to zero. The associated costs are costs of performing or executing the activities on the locomotive wheels 324, 326, and the inventory wheels. An exemplary objective function may be represented as follows: wherein aj is an axle, A represents a set of inventory axles A and locomotive axles AL, A1 represents a set of available inventory axles, AL represents a set of locomotive axles, wjl represents left wheel of a locomotive axle or an inventory axle, and wjr represents right wheel of the locomotive axle or the inventory axle.

The objective function (1), comprises costs including, and is cost of one inch material removed while truing a locomotive axle or an inventory axle. Clr"e is cost of truing per axle, CRe is cost of replacing a locomotive axle by an inventory axle; cScrap is cost of scrapping a locomotive axle, and Csl'"" is cost of shimming a locomotive axle or an inventory axle. Furthermore, the objective function (1) includes decision variables including x^ , is an amount of rim reduction required in a left wheel of a locomotive axle or an inventory axle, x™r is an amount of rim reduction required in a right wheel of the locomotive axle or the inventory axle, 8'a"" is a truing decision variable, aaa is a replacement decision variable, 8^arp is a scrapping decision variable, S^'"" is a shimming decision variable.

[0025] Furthermore, the processing subsystem 308 includes the constraints 340 formulated based upon at least one of the locomotive input wheel measurements 328 corresponding to the locomotive wheels 324, 326, the inventory input wheel measurements 336 corresponding to the inventory wheels mounted on the inventory axle 303, the measurement thresholds 330, the tolerances 332, the look up table 334 and the decision variables. The constraints 340, for example, include wheel constraints, wheels-within-axle constraints, wheels-within-truck constraints, wheels-across-truck constraints, or combinations thereof.

Wheel Constraints

[0026] As used herein, the term "wheel constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a wheel level violation exists in a locomotive wheel or an inventory wheel, and enable a decision variable to obviate the wheel level violation. For ease of understanding, the wheel constraints are explained with reference to the first locomotive wheel 320, the second locomotive wheel 322, and the first truck first axle 314; however the techniques explained are applicable to each of the locomotive wheels 324, 326, or the inventory wheels. Satisfaction of the wheel constraints determines whether the wheel level violation exists in the first locomotive wheel 320. For example, satisfaction of the wheel constraints determines whether the wheel level violation exist the first locomotive wheel 320 by comparing locomotive input wheel measurements of the first locomotive wheel 320 with the respective measurement thresholds 330. Furthermore, satisfaction of the wheel constraints determines the existence of the wheel level violation in the first locomotive wheel 320 when the locomotive input wheel measurements of the first locomotive wheel 320 crosses the respective measurement thresholds 330.

[0027] The satisfaction of the wheel constraints either results in enablement of one or more of the decision variables for the first locomotive wheel 320 and the second locomotive wheel 322 mounted on the first truck first axle 314 when a presence the wheel level violation is determined in the first locomotive wheel 320, or results in disablement of one or more of the decision variables when the wheel level violation does not exist in the first locomotive wheel 320. For example, when a wheel level violation is determined in the first locomotive wheel 320, a truing decision variable or a scrapping decision variable may be enabled for the first locomotive wheel 320 and the second locomotive wheel 322. The enablement of the truing decision variable results in inclusion of the truing activity in the recommendation 342 to true the first locomotive wheel 320 and the second locomotive wheel 322 mounted on the first truck first axle 314. Furthermore, the enablement of the scrapping decision variable results in inclusion of the scrapping activity in the recommendation 342 to scrap the first truck first axle 314.

[0028] An exemplary wheel constraint that result in determination of the existence of the wheel level violation is shown in equation (2): where li[" is a locomotive input wheel measurement or an inventory wheel measurement namely flange height of a locomotive wheel or inventor wheel, ThhH is a measurement threshold namely flange height threshold, 8la"K is a decision variable namely truing decision variable, S^arp is a decision variable namely scrapping decision variable.

[0029] The wheel constraint of equation (2) compares the flange height l![" of the locomotive wheels 324, 326 and the inventory wheels to the flange height threshold Th1'" . In one embodiment, the flange height threshold Th''H is the maximum flange height threshold. Particularly, the satisfaction of the wheel constraint of equation (1) determines whether the flange height L™ of the locomotive wheels 324, 326 and the inventory wheels is greater than the flange height threshold Th''" . When the wheel constraint of equation (2) determines that the flange height ll[" of the locomotive wheels 324, 326 and the inventory wheels is greater than the flange height threshold Th1'", the wheel level violation is determined and the truing decision variable or the scrapping decision variable are enabled.

[0030] Another exemplary wheel constraint that results in determination of the existence of the wheel level violation is shown in the below equation (3): where ll'J is an input wheel measurement namely flange thickness of a locomotive wheel or an inventory wheel, Th''' is a measurement threshold namely flange thickness threshold, S]""1 is a decision variable namely truing decision variable, and S^arp is a decision variable namely scrapping decision variable. The wheel constraint of equation (3) compares the flange thickness L''J of the locomotive wheels 324, 326 and the inventory wheels to the flange thickness threshold Th1'' . In one embodiment, the flange thickness threshold Th'1 is a minimum flange thickness threshold. Particularly, the satisfaction of the wheel constraint of equation (2) determines whether the flange thickness L''J of the locomotive wheels 324, 326 and the inventory wheels is greater than the flange thickness threshold ThH . When the wheel constraint of equation (3) determines that the flange thickness L''J of the locomotive wheels 324, 326 and the inventory wheels is less than the flange thickness threshold Th1'" , the wheel level violation is determined and the truing decision variable or the scrapping decision variable are enabled.

[0031] Still another exemplary wheel constraint that results in determination of the existence of the wheel level violations is shown in the equation (4): where L™ is an input wheel measurement namely rim thickness of a locomotive wheel or an inventory wheel, x*' is an amount of rim reduction required in a locomotive wheel or an inventory wheel determined based upon a look up table, ThRI is a measurement threshold namely rim thickness threshold, and 8^arp is a decision variable namely scrapping decision variable. The wheel constraint of equation (4) compares a difference of the rim thickness LRI and an amount of rim reduction required xRI from the locomotive wheels 324, 326 and the inventory wheels to a L," of the locomotive wheels 324, 326 and the inventory wheels to the rim thickness threshold Thm . Particularly, the satisfaction of the wheel constraint of equation (4) determines whether the difference of the rim thickness L1" and an amount of rim reduction required in the locomotive wheel or the inventory wheel xRJ is greater than the rim thickness threshold Thm . In one embodiment, the rim thickness threshold ThRI is a minimum rim thickness threshold. When the wheel constraint of equation (4) determines that the difference of the rim thickness LRI and the amount of rim reduction xRI is less than the rim thickness threshold ThRI, the wheel level violation is determined, and the scrapping decision variable enabled.

[0032] Still another exemplary wheel constraint may be represented by equation (5): (5) where L™' is an input wheel measurement namely reference groove reading of a locomotive wheel or an inventory wheel, xR7 is an amount of rim reduction required in a locomotive wheel or an inventory wheel determined based on a look up table, Thm is a measurement threshold namely rim thickness threshold, and 8^arp is a decision variable namely scrapping decision variable. The wheel constraint of equation (5) compares a difference of the reference groove reading LRG and an amount of rim reduction required in the locomotive wheels 324, 326 and the inventory wheels xRI to the rim thickness threshold 77?'" . Particularly, the satisfaction of the wheel constraint of equation (5) determines whether the difference of the reference groove reading LRC' and the amount of rim reduction required in the locomotive wheels 324, 326 and the inventory wheels xR1 is greater than the rim thickness threshold ThRI. When the wheel constraint of equation (4) determines that the difference is less than the rim thickness threshold ThRI, the wheel level violation is determined and the scrapping decision variable £*""* is enabled. Wheel s-within-axle constraints

[0033] As used herein, the term "wheels-within-axle constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether an axle level violation exists in a locomotive axle or an inventory axle, and enable a decision variable to obviate the axle level violation. Satisfaction of the wheels-within-axle constraints determines whether the axle level violation exists in the locomotive axles 325, 327 and the inventory axles 303. For ease of understanding, the wheels-within-axle constraints are explained with reference to the first truck first axle 314, and the first locomotive wheel 320, and the second locomotive wheel 322 mounted on the first truck first axle 314, however the techniques explained are applicable to each of the locomotive axles 325, 327 and the inventory axles 303. For example, satisfaction of the wheels-within-axle constraints determines whether the axle level violations exist in the first truck first axle 314. When it is determined that the axle level violation exists in the first truck first axle 314, the scrapping decision variable 8sajarpox the truing decision variable 8la"'e is enabled for the first truck first axle 314.

[0034] In one embodiment, the satisfaction of the wheels-within-axle constraints determines the axle level violations in the first truck first axle 314 by:

a.) determining a difference (axle level difference) by subtracting a reference groove reading of the first locomotive wheel 320 from a reference groove reading of the second locomotive wheel 322 mounted on the first truck first axle 314;

b.) determining the axle level violation in the first truck first axle 314 when the axle level difference crosses the axle level tolerance or a constant.

[0035] In another embodiment, the satisfaction of the wheels-within-axle constraints determines the axle level violations in the first truck first axle 314 by:

a.) determining a first difference (first axle level difference) by subtracting a rim thickness reduction required in the first locomotive wheel 320 mounted on the first truck first axle 314 from a reference groove reading of the first locomotive wheel 320;

b) determining a second difference (second axle level difference) by subtracting a rim thickness reduction required in a second locomotive wheel 322 mounted on the first truck first axle 314 from a reference groove reading of the second locomotive wheel 322;

c.) determining a third difference (third axle level difference) by subtracting the first axle level difference from the second difference; and

d.) determining the axle level violation in the first truck first axle 314 when the third axle level difference crosses the axle level tolerance or a constant.

[0036] When the axle level violation is determined in the first locomotive wheel 320 and the second locomotive wheel 322, then the scrapping decision variable or the amount of rim reduction required decision variable is enabled.

[0037] In one embodiment, the wheels-within-axle constraints may be represented by the equations (6) and (7): where L*l'tl is an input wheel measurement namely reference groove reading of a left locomotive wheel or a left inventory wheel mounted on axle i, L!^r is an input wheel measurement namely reference groove reading of a right locomotive wheel or a right inventory wheel mounted on axle i, M is a constant, i is a number of axle, x*l is an amount of rim reduction required in the left locomotive wheel or a left inventory wheel determined based on a look up table, x'"r is a decision variable namely an amount of rim reduction required in the right locomotive wheel or the right inventory wheel determined based on a look up table, ta is an axle level tolerance, S^arp is a decision variable namely scrapping decision variable, and 5'a"'e is a decision variable namely truing decision variable. Wheels-within-truck constraints

[0038] As used herein, the term "wheels-within-truck constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a combination of axles, mounted on same truck or to be mounted on the same truck, have a truck level violation, and enable a decision variable to obviate the truck level violation; wherein the combination comprises a locomotive axle and another locomotive axle, a locomotive axle and an inventory axle, and an inventory axle and another inventory axle. In one embodiment, the satisfaction of wheels-within-truck constraints determines whether the locomotive axles 325, 327 have the truck level violation. In another embodiment, the satisfaction of wheels-within-truck constraints determine whether one or more of the inventory axles 303 if selected for replacing one or more of the locomotive axles 325, 327 will result in the truck level violation. When the satisfaction of the wheels-within-constraints result in determination of the truck level violation in the locomotive axles 35,327, or the inventory axles 303 then the shimming decision variable or the replacement decision variable are enabled for the locomotive axles 35,327 and the inventory axles 303. For example, when the satisfaction of the wheels-within-constraints determines that the truck level violation exists in the first truck first axle 314 and the first truck second axle 316, then the shimming decision variable or the replacement decision variable are enabled for the first truck first axle 314 and the first truck second axle 316.

[0039] The satisfaction of the wheels-within-truck constraints determines the axle level violations in two different axles mounted on the same truck or to be mounted on the same truck by:

a.) determining a difference of reference groove readings of two wheels mounted on the two different axles, wherein the two axles may be a combination of one of the locomotive axles 325, 327 and one of the inventory axles 303, or the two axles may be a combination of two of the locomotive axles 325, 327, or the two axles may be a combination of two of the inventory axles;

b.) comparing the difference (truck level difference) to a truck level tolerance; and

c.) determining a truck level violation in the axles when the truck level difference crosses the truck level tolerance. When the axle level violation is determined in the axles, the shimming decision variable, or the amount of rim reduction required decision variable or the replacement decision variable are enabled for one or both of the two axles.

[0040] In one embodiment, the wheels-within-truck constraints may be represented by the equations (8)-(l 1): L1^, is a reference groove reading of a left locomotive wheel in a locomotive axle aj 1 in a truck T, L^j]r is a reference groove reading of a right locomotive wheel in the locomotive axle aj 1 in the truck T L^2J, L*°2J is a reference groove reading of a left locomotive wheel of another locomotive axle aj2 in the truck T, r, is a truck level tolerance, sK0 is increase in reference groove of a wheel by shimming the wheel, 8^"" is a shimming decision variable, «a/ „, is decision variable namely replacement decision variable for replacing the locomotive axle aj 1 by an inventory axle ai, and aai a ^ is decision variable namely replacement decision variable for replacing the locomotive axle aj2 by an inventory axle ai. Wheels-across-trucks constraints

[0041] As used herein, the term "wheels-across-trucks constraints" refers to constraints that are required to be satisfied while minimizing an objective function to determine whether a first axle of a first truck and a second axle of a second truck have a locomotive level violation, and enable a decision variable to obviate the locomotive level violation; wherein the first axle and the second axle comprises a locomotive axle, an inventory axle, or combinations thereof. 272993-2

[0042] The satisfaction of the wheels-across-trucks constraints determines the locomotive level violations in a first axle and a second axle, the first axle is mounted or to be mounted on a first truck and the second axle is mounted or to be mounted on a second truck, by:

a.) determining a difference (hereinafter referred to as 'locomotive level difference') of a reference groove reading of a wheel mounted on the first axle from a reference groove reading of another wheel mounted on the second axle;

b.) comparing the locomotive level difference to a locomotive level tolerance; and

c.) determining a locomotive level violation in the first axle and the second axle when the locomotive level difference crosses the locomotive level tolerance.

[0043] When the locomotive level violation is determined in the axles, the shimming decision variable, or the amount of rim reduction required decision variable or the replacement decision variable are enabled for the first axle or the second axle.

[0044] In one embodiment, the processing subsystem 308 includes a reset module 344 that updates locomotive input wheel measurements or inventory wheels measurements of one or more of the locomotive wheels 324, 326 or the inventory wheels 303 when a truing decision variable is enabled for the one or more of the wheels 324, 326. For example, the rest module 344 updates the locomotive input wheel measurements or inventory wheels measurements of the one or more of the locomotive wheels 324, 326 or the inventory wheels 303 based on the reset values 339.

[0045] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims:

1. A locomotive service management system, comprising: a processing subsystem that generates a recommendation by minimizing an objective function by satisfying a plurality of constraints formulated based upon at least one of a plurality of locomotive input wheel measurements corresponding to locomotive wheels mounted on respective locomotive axles in one or more trucks of a locomotive, a plurality of inventory input wheel measurements corresponding to inventory wheels mounted on respective inventory axles, a plurality of measurement thresholds, a plurality of tolerances, a look up table, and a plurality of decision variables, wherein the objective function comprises at least one of: the plurality of decision variables corresponding to one or more activities and associated costs for implementing the one or more activities on at least one of the locomotive wheels, the respective locomotive axles, the inventory wheels, and the respective inventory axles.

2. The locomotive service management system of claim 1, wherein the plurality of locomotive input wheel measurements and the plurality of inventory wheel measurements comprises a flange height, a flange thickness, a rim thickness, a reference groove reading, or combinations thereof of the plurality of locomotive wheels and the plurality of inventory wheels.

3. The locomotive service management system of claim 1, wherein the plurality of decision variables comprise a truing decision variable, a scrapping decision variable, a replacement decision variable, a shimming decision variable, or combinations thereof.

4. The locomotive service management system of claim 1, wherein the objective function is minimized to minimize a total cost of executing the recommendation on at least one of the locomotive wheels, the respective locomotive axles, the inventory wheels, and the respective inventory axles.

5. The locomotive service management system of claim 3, wherein the recommendation comprises one or more of the activities to be implemented on at least one of the locomotive wheels, the inventory wheels, the respective locomotive axles, and the respective inventory axles; and wherein the activities comprise a scrapping activity, a replacement activity, a truing activity, a shimming activity, or combinations thereof.

6. The locomotive service management system of claim 5, wherein implementation of the one or more of the activities on the at least one of the locomotive wheels, the inventory wheels, the respective locomotive axles, and the respective inventory axles obviates a wheel level violation, an axle level violation, a truck level violation, and a locomotive level violation.

7. The locomotive service management system of claim 6, wherein the plurality of constraints comprises wheel constraints, wheels-within-axle constraints, wheels-within-truck constraints, wheels-across-trucks constraints, or combinations thereof.

8. The locomotive service management system of claim 7, wherein the processing subsystem minimizes the objective function by satisfying the wheel constraints to: determine whether a wheel mounted on a respective axle has the wheel level violation based upon the wheel constraints; and enable the truing decision variable or the scrapping decision variable for the axle when the wheel mounted on the axle has the wheel level violation, wherein enabling the truing decision variable results in inclusion of the truing activity in the recommendation to true both wheels mounted on the axle, and enabling the scrapping decision variable results in inclusion of the scrapping activity in the recommendation to scrap the axle, and wherein the wheel is one of the locomotive wheels or one of the inventory wheels, and wherein the axle is one of the respective locomotive axles or one of the inventory axles.

9. The locomotive service management system of claim 8, wherein the processing subsystem minimizes the objective function by satisfying the wheel constraints to: compare one or more input wheel measurements of the wheel to respective measurement thresholds in the plurality of measurement thresholds; and determine an existence of the wheel level violation in the wheel when the one or more input wheel measurements crosses the respective measurement thresholds, wherein the input wheel measurements comprise one or more of the plurality of locomotive input wheel measurements or one or more of the plurality of inventory input wheel measurements.

10. The locomotive service management system of claim 9, wherein the processing subsystem determines whether the wheel mounted on the axle has the wheel level violation by satisfying the wheel constraints by: comparing a flange height of the wheel to a maximum flange height threshold; comparing a flange thickness of the wheel to a minimum flange thickness threshold; and comparing a difference, of a rim thickness of the wheel and a determined amount of material reduction required in the wheel, to a minimum rim thickness threshold; and determining an existence of the wheel level violation in the wheel when the flange height crosses the maximum flange height threshold, or the flange thickness crosses the minimum flange thickness threshold, or the difference crosses the minimum rim thickness threshold.

11. The locomotive service management system of claim 7, wherein the processing subsystem minimizes the objective function by satisfying the wheels-within-axle constraints by: determining whether an axle in the respective locomotives axles or the respective inventory axles has the axle level violation based upon the wheels-within-axle constraints; and enabling the truing decision variable or the scrapping decision variable for the axle when the axle has the axle level violation, wherein enabling the truing decision variable results in inclusion of the truing activity in the recommendation to true both wheels mounted on the axle, and enabling the scrapping decision variable results in inclusion of the scrapping activity in the recommendation to scrap the axle.

12. The locomotive service management of claim 7, wherein determining whether an axle in the respective locomotive axles or the respective inventory axles has the axle level violation by satisfying the wheels-within-axle constraints, comprises: determining a first difference by subtracting a rim thickness reduction required in a first wheel mounted on the axle from a reference groove reading of the first wheel; determining a second difference by subtracting a rim thickness reduction required in a second wheel mounted on the axle from a reference groove reading of the second wheel; determining a third difference by subtracting the first difference from the second difference; determining an axle level violation in the axle when the third difference crosses the axle level tolerance. wherein the first difference is indicative of an updated reference groove reading of the first wheel after potential truing activity performance on the first wheel, and wherein the second difference is indicative of an updated reference groove reading of the second wheel after potential truing activity performance on the second wheel.

13. The locomotive service management system of claim 12 wherein the processing subsystem enables the truing decision variable for the axle when the third difference is substantially zero or the updated reference groove reading of the first wheel is substantially equal to the updated reference groove reading of the second wheel.

14. The locomotive service management of claim 7, wherein the processing subsystem minimizes the objective function by satisfying the wheels-within-truck constraints by: determining a truck level difference of reference groove readings of two wheels mounted on two different axles mounted on a single truck or to be mounted on the single truck ; comparing the truck level difference to a truck level tolerance; and determining the truck level violation in the two different axles when the truck level difference crosses the truck level tolerance, wherein the two different axles may be a combination of one of the respective locomotive axles and one of the respective inventory axles, or the two axles may be a combination of two of the respective locomotive axles, or the two axles may be a combination of two of the respective inventory axles.

15. The locomotive service management system of claim 14, wherein the processing subsystem enables the shimming decision variable or the amount of rim reduction required decision variable or the replacement decision variable for one or both of the two different axles when the truck level violation is determined in the two different axles.

16. The locomotive service management of claim 7, wherein the processing subsystem minimizes the objective function by satisfying the wheels-across-trucks constraints by: determining a locomotive level difference of a reference groove reading of a wheel mounted on a first axle of a first truck from a reference groove reading of another wheel mounted on a second axle of a second truck; comparing the locomotive level difference to a locomotive level tolerance; and determining a locomotive level violation in the first axle and the second axle when the locomotive level difference crosses the locomotive level tolerance.

17. The locomotive service management of claim 16, wherein the first axle is one of the respective locomotive axles and the second axle is one of the respective inventory axles, or the first axle and the second axle are two of the respective locomotive axles, or the first axle and the second axle are two of the respective inventory axles.

18. The locomotive service management system of claim 16, wherein the processing subsystem enables the shimming decision variable or the amount of rim reduction required decision variable or the replacement decision variable for at least one of the first axle and the second axle when the locomotive level violation is determined in the first axle and the second axle.

19. The locomotive service management of claim 1, wherein the plurality of measurement thresholds comprise a maximum flange height threshold, a minimum flange thickness threshold, a minimum rim thickness threshold, a minimum reference grove threshold, or combinations thereof.

20. The locomotive service management of claim 1, wherein the plurality of tolerances comprise an axle level tolerance, a truck level tolerance, a locomotive level tolerance, a maximum reference groove axle level tolerance, a maximum reference groove truck level tolerance, a maximum reference groove locomotive level tolerance, or combinations thereof.