Patent Publication Number: US-2019168728-A1

Title: System and Method for Adaptive Braking

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a method of controlling a train equipped with an electronically controlled pneumatic (ECP) braking system, 
     Description of Related Art 
     A traditional train braking system uses pneumatic valves to control and generate brake applications on the rail cars along the length of the train, which train, in an example, can include a locomotive and one, or two, or more rail cars. In general, this traditional system includes a brake pipe that runs the entire length of the train and which supplies air from an air compressor located the locomotive to air reservoirs mounted on each of the rail cars and the locomotive. When it is desired to apply the brakes of the train, one or more manually operated brake control valves in the locomotive are adjusted by an operator thereby causing a reduction in the brake pipe air pressure. As the brake pipe pressure reduces, the brake service portion on each rail car diverts pressurized air from the rail car&#39;s brake cylinders, whereupon the brakes of the rail car engage to a level related to the pressure of the air remaining in the brake cylinders, i.e., less air pressure in the brake cylinders equates to a higher level of braking. In order to release the brakes, the engineer charges the brake pipe with pressurized air supplied from the air compressor on the locomotive. This increases the air pressure within the brake pipe resulting in a reduced flow of air from the air reservoir on the rail cars further resulting in reduced braking. 
     One of the drawbacks of such air brake systems is reaction time. For example, for trains with, for example, 100 or more rail cars, it can take up to two minutes or more from the time the manually operated brake control valves are adjusted for the reduction in the brake pipe air pressure to propagate from the locomotive to the rail car at tail end of the train. This results in rail cars applying brakes at different points in time. This uneven braking can cause significant in-train forces to build up between the rail cars in a train. In order to reduce the propagation delay, most trains were equipped with a caboose or a brake van at the trailing end of the train. Today, the caboose is replaced with an End-of-Train (EOT) device that is coupled to the end of the brake pipe to serve a similar purpose of the caboose. 
     In contrast, ECP braking uses electronic controls which make it possible to activate air-powered brakes on the cars significantly faster and synchronously. On an ECP-equipped train, the rail cars are equipped with a trainline (a physical communication cable) that runs the length of the train. The trainline is used to (a) supply power to the electronic components installed on the cars and (b) to facilitate electronic communication between the locomotive, the rail cars and an End of Train (EOT) device, i.e., send commands from the locomotive and receive feedback from the rail cars and an End of Train (EOT) device. 
     ECP braking provides many benefits over the traditional braking system. For example, since all the rail cars receive the brake command at the same time, the brakes of the rail cars can be applied more uniformly and substantially instantaneously. This can provide better train braking control, can shorten a stopping distance of the train, and can lower the risk of derailment or of coupling breakage. 
     Further, since the rail cars can also send their status to the locomotive at the front, the train operator, for example, the engineer, can monitor the state of the rail cars and know at any given time the braking capabilities available. 
     In typical operation, the ECP brakes on a train are required to be operated in accordance with an ECP braking mode of operation governed by the Association of American Railroads (AAR)S-4200 standard braking requirements. In accordance with the S-4200 standard, the brakes of all of the rail cars of the train are controlled during operation of the train to the same percentage of braking during braking operations of the train. 
     For example, in accordance with the S-4200 standard, a processor based head end unit (HEU) in the locomotive can output a braking command on a trainline, e.g., a 30% braking command, which braking command is received by a processor of each rail car of the train communicatively coupled to the trainline. In response to receiving this braking command, the processor of each rail car causes the pneumatic brakes of the rail car to be set to the commanded value, in this example 30% of full braking. In this manner, the brakes of all of the rail cars of the train can be commanded to be set to the same percentage or level of braking at about the same time, thereby reducing and/or minimizing the levels of in-train forces on the couplers of the train that are used to connect the locomotive and the rail cars of the train that would appear on the couplers if the brakes of the rail cars were applied at different times. 
     In general, brakes of rail cars in a train enable deceleration, controlled acceleration (downhill), or keep the rail cars standing when parked. The functioning of proper brakes of rail cars in a train is essential and critical. Often times, a train including tens of cars travelling on a mainline track at a typical travelling speed can require over a mile (or kilometer) or two or more to come to a full stop. Braking of a train (comprised of a locomotive and attached rail cars) is initiated, typically, from the locomotive and the individual brakes on each of the rail cars typically respond to a signal in the form of ‘air pressure variance’ or ‘electronic initiation’ to trigger the braking systems to function as desired and bring the train to a stop or to slow it down, for example, as described above for the S-4200 standard. Braking efficiency can vary based on speed of the train, its momentum (based on the cargo it&#39;s carrying), external factors like temperature and wind, and urgency of braking. Today&#39;s braking systems, operating in accordance with the S-4200 standard, do one thing well, namely, apply the brakes in a manner that does not distinguish or have prejudice for different reasons for braking or the prevalent conditions in the train and its cargo. 
     Consequently, there is a need for an improved braking solution that overcome at least some of the deficiencies of the braking solutions of today. 
     SUMMARY OF THE INVENTION 
     Generally, provided is an intelligent braking system and method for a train that has the ability to request one or more braking profiles from one or more groups of railcars within the train and further having the ability to alter the composition of the one or more groups of rail cars as well as the one or more braking profiles for each of the one or more groups of rail cars. 
     More specifically, provided are an improved system and method for intelligent or adaptive braking of one or more or all of the rail cars of a train that can, for each rail car of the train, optimize the braking force for each car brake unit based on one or more or any combination of the condition of the rail car, the cargo (or lack of cargo) on board the rail car, speed of travel, and/or any other physical force or condition that can influence the effectiveness of the overall braking of the train when initiated. 
     According to a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system and method can determine dynamic behavior one or more rail cars of a train, the brakes of said one or more rail cars, or both during braking to, in a preferred and non-limiting example, embodiment, or aspect, desirably cause a stable braking profile safeguarding the train and its cargo and any wayside installation or entity. 
     In a preferred and non-limiting example, embodiment, or aspect, the train can have electronically controlled braking, such as ECP braking described above, that can be modified in the manner discussed herein to operate outside of the S-4200 standard. In a preferred and non-limiting example, embodiment, or aspect, the train can have conventional pneumatic (non-electronically triggered) controlled braking that can be modified and used accordingly. In a preferred and non-limiting example, embodiment, or aspect, a human machine interface (HMI) can be provided for the engineer (or train operator) to enter a speed, or a location, or both that can define the desired train braking to be achieved by the system and method for intelligent or adaptive braking described herein. 
     Today&#39;s S-4200 compliant braking systems are non-discriminative. Namely, during braking of the train, the brakes of each rail car are commanded to be set to the same percentage of braking. In response to such brake commands, and except for minor pneumatic and mechanical variations between the pneumatic brakes of each rail car, in response to a train brake command the brakes of each rail car respond in the same manner, i.e., the brakes of each rail car are set to the same percentage of braking as the brakes of each other rail car. In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking described herein can selectively set the brakes of each rail car of a train to a percentage of braking selected for the rail car, which percentage of braking can vary between 0% braking and 100% braking (or 120%—emergency braking), and which percentage of braking can be the same or different than the percentage of braking of each other rail car of the train. In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking described herein can cause the brakes of each rail car to be set to a percentage of braking that can optimize braking efficiency of the entire train. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking described herein can reduce or eliminate the role of the engineer (or train operator) by automating the capabilities on-board the locomotive. In a preferred and non-limiting example, embodiment, or aspect, a train operator may determine, via a map (for example), a desired location where the train is expected to slow down to a particular speed or come to a full stop and can input this information into a locomotive head-end unit (HEU). In response to this input, the system and method for intelligent or adaptive braking described herein can cause the brakes of each rail car to be set to a percentage of braking specifically selected for said rail car to achieve the particular speed or stop at the desired location, desirably without further train operator input to achieve the particular speed or stop at the desired location. 
     Current locomotive HMIs allow control of the brake system, but not entry of the desired percentage of braking specifically selected for each rail car. Other systems calculate a desired braking outcome and either “coach” the engineer how to enter controls to achieve that outcome, or may even actively couple to the controls to achieve that outcome. In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking described herein allows the train operator to determine and input the desired outcome, and then let the system calculate and execute the required braking to achieve the desired outcome. 
     In a preferred and non-limiting example, embodiment, or aspect, overall braking of a train and, more particularly, the selective control and setting of the brakes of each rail car of the train independent of the control and setting of the brakes of each other rail car of the train can be determined or calculated by the HEU. In a preferred and non-limiting example, embodiment, or aspect, such calculation can increase the longevity of the braking components by reducing wear on the brake shoes or pads and reduce stress on the overall braking system of each rail car. This can result in improved cost efficiencies, and improved safety for the train, the cargo, the crew and anyone/anything in the vicinity of the train traveling, for example, on a mainline track. In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking described herein may not require the train operator to mentally determine brake system parameters required to achieve the desired braking outcomes. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking can have one or more sensors for sensing braking elements and/or other operational aspects or features of one or more of the rail cars, which one or more sensors can provide the HEU with data that the HEU can use to determine the brakes on each car that need to be triggered, when, and how much braking force needs to be exerted the brakes on the car when the train is travelling on a mainline track. 
     Historically, a train operator inspects the locomotive before and during operation, as well as checks speed, air pressure, battery, and other systems of the train while travelling on a mainline track. In a preferred and non-limiting example, embodiment, or aspect, it is envisioned that, with the help of sensors on the rail cars, automated and intelligent decision making regarding setting the brakes of each rail car to a percentage of braking specifically selected for said rail car to achieve a particular speed or stop of the entire train at the desired location, a locomotive having the system and method for intelligent or adaptive braking described herein can reduce or eliminate the decision making role of the train operator(s) (e.g., a locomotive driver and engineer) regarding such setting of the brakes. 
     In a preferred and non-limiting example, embodiment, or aspect, a train having, for example, ten rail cars can be controlled to optimize braking based on the HEUs understanding of dynamic behavior of or more of the rail cars, acquired, for example, from sensors on one or more of all of said cars, having a determined weight of cargo. In a preferred and non-limiting example, embodiment, or aspect, the HEU can determine a desired, desirably optimal, braking of one or more rail cars of the train based on the number of rail cars, the type of cargo being transported, and the sequence of coupling of the rail cars. Based on this information, the HEU can compute a desired, desirably optimal, braking sequence or braking scenario that includes determining which brakes of one or more or all of the rail cars to trigger for braking and the braking percentage the brakes of each such rail car exerts to desirably provide for smooth and safe braking of the entire train. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking can compute the percentage of braking not for each rail car individually, but for a group or subset of cars. For example, in a train with ten rail cars, the system and method for intelligent or adaptive braking can determine percentages of braking for the group of rail cars 1, 2, 3, 4, 5 and, at another time, determine percentages of braking for the group of rail cars 6, 7, 8, 9, 10, and so on, where the brakes of each rail car of each group can be set to a percentage of braking selected for the rail car, which percentage of braking can vary between 0% braking and 120% (emergency) braking, and which percentage of braking can be the same or different than the percentage of braking of each other rail car of the group. In a preferred and non-limiting example, embodiment, or aspect, it is also envisioned that normally deployed pneumatic (non-electronically triggered) braking system may also be modified and used accordingly. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking can determine the braking force to be applied by the brakes of each rail car based not only on the dynamic forces acting on the car (because of the load, the speed, and the environmental factors) but also based on the condition of the brake shoes, more particularly the amount of wear on the brake shoes or pads. In a preferred and non-limiting example, embodiment, or aspect, this can mean that the system and method for intelligent or adaptive braking can set the percentage of braking of the brakes on each rail car of the train independently of the setting the percentage of braking of the brakes on each other rail car of the train in a manner to extend the life of brake shoes or pads. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking can determine the braking percentage to be applied by one or more of the cars based on a condition one or more wheels of the rail car and any present imperfections of said wheel(s). 
     In a preferred and non-limiting example, embodiment, or aspect, each rail car can have one or more sensors that can measure the weight of each car, and a central braking component, e.g., the HEU, can utilize information about the cargo in each car, speed of travel of the train, and prevalent environment conditions to determine a unique percentage of braking for each rail car. In a preferred and non-limiting example, embodiment, or aspect, the brakes of each car will receive a percent braking command specific to that car that will allow synchronous braking in all the railcars, with or without the application of uniform braking forces, to slow the train and/or to bring the train to a safe stop in view of the prevalent environment conditions. Environment conditions can include data regarding any weather condition, such as, for example, temperature, pressure, moisture, wind conditions, seasonal information that may be indicative of extreme travel like snow, ice, sleet, leaves (during fall season), etc. 
     In a preferred and non-limiting example, embodiment, or aspect, the system and method for intelligent or adaptive braking can calculate the required brake application necessary to achieve an operational outcome upon train operator entry of a desired speed, or a desired speed and location to achieve that speed. 
     Further preferred and non-limiting embodiments or aspects are set forth in the following numbered clauses. 
     Clause 1: A method of braking a plurality of rail cars of a train while travelling or moving on a mainline track that includes a locomotive processor onboard a locomotive of the train in communication with a rail car processor of each rail car of the train, the method comprising: (a) the locomotive processor providing to each rail car processor of a first subset of the rail cars a unique braking command that is independent of the braking command provided to each other rail car processor of the first subset of rail cars, wherein each braking command includes a level or percentage of braking the brakes of the rail car are to assume; and (b) in response to the braking command provided to each rail car processor of the first subset of the rail cars in step (a), the rail car processor causing the brakes of the rail car to assume the level or percentage of braking included in the unique braking command provided to the rail car processor. 
     Clause 2: The method of clause 1, wherein the unique braking command provided to each rail car processor of the first subset of the rail cars can be based on data regarding the rail car, the train, or both provided to the locomotive processor. 
     Clause 3: The method of clause 1 or 2, wherein the data can include predicted or actual data regarding one or more of the following: a health of the braking system of one or more of the rail cars of the train; one or more environmental conditions in a vicinity of the train; dynamic behavior of one or more rail cars of the train while travelling or moving or during braking; topology of a track between a present location and a future location of the train; and a load carried by one or more of the rail cars. 
     Clause 4: The method of any one of clauses 1-3, wherein the data regarding the health of the braking system can include one or more of the following: actual or estimated wear or life of a brake shoe/pad; actual or estimated wear of the brake shoe/pad based on the load carried by one or more of the rail cars of the train; and actual or estimated wear of the brake shoe/pad based on G forces of one or more rail cars of the train while travelling or moving. 
     Clause 5: The method of any one of clauses 1-4, wherein the actual or estimated wear or life of a brake shoe/pad can be determined from optical data of the brake shoe/pad acquired by a camera or based on an output of an electrical/electronic circuit detecting the useable brake material or amount of useable brake material. 
     Clause 6: The method of any one of clauses 1-5, wherein the one or more environmental conditions can include one or more of the following: temperature, wind speed, wind direction, humidity, the presence or absence of ice or snow on the track upon which the train is travelling, and precipitation. 
     Clause 7: The method of any one of clauses 1-6, wherein the data regarding the one or more environmental conditions can be received wirelessly by the locomotive processor from a source remote from the train. 
     Clause 8: The method of any one of clauses 1-7, wherein the data regarding the dynamic behavior of one or more rail cars of the train while travelling or moving or during braking can include one or more of the following: a force on a coupler; rate of change of velocity (acceleration or deceleration) of the train; G forces of one or more rail cars of the train; pitch or roll of one or more rail cars of the train; and track adhesion is determined based on a difference between a linear speed of a wheel of at least one rail car and a speed of the train. 
     Clause 9: The method of any one of clauses 1-8, wherein the data regarding topology can include one or more of the following: track gradient; track curvature; and track elevation. 
     Clause 10: The method of any one of clauses 1-9, wherein the load carried by one of the rail cars of the train can be determined by one or more load cells mounted to the rail car. 
     Clause 11: The method of any one of clauses 1-10, further including, following step (b): (c) the locomotive processor can provide to each rail car processor of a second subset of the rail cars a unique braking command that is independent of braking command provided to each other rail car processor of the second subset of rail cars; and (d) in response to the braking command provided to each rail car processor of the second subset of the rail cars in step (c), the rail car processor can cause the brakes of the rail car to assume the level or percentage of braking included in the unique braking command provided to the rail car processor, wherein the first and second subsets of rail cars are different. 
     Clause 12: A method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, wherein each rail car includes a rail car processor that is operative for controlling the brakes of the rail car, the method comprising: (a) each rail car processor of a first subset of the rail cars receiving a braking command prepared exclusively for the rail car processor; and (b) in response to step (a), each rail car processor of the first subset of the rail cars causing the brakes of its rail car to assume a level or percentage of braking included in the braking command received by the rail car processor in step (a). 
     Clause 13: The method of clause 12, further including: (c), following step (b), each rail car processor of a second subset of the rail cars can receive a braking command prepared exclusively for the rail car processor; and, (d) in response to step (c), each rail car processor of the second subset of the rail cars can cause the brakes of its rail car to assume a level or percentage of braking included in the braking command received by the rail car processor in step (c), wherein the first and second subsets of rail cars can be different. 
     Clause 14: A method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, comprising: (a) a locomotive processor providing to each rail car processor of a first subset of the rail cars a braking command that is prepared exclusively for the rail car processor; (b) each rail car processor of the first subset of rail cars receiving the braking command provided to the rail car processor in step (a); (c) each rail car processor of the first subset of rail cars processing the braking command received in step (b); and (d) each rail car processor of the first subset of rail cars setting the brakes of its rail car to a level or percentage of braking included in the braking command processed in step (c) for the rail car processor, whereupon the brakes of each rail car of the first subset of rail cars are set to the same or a different percentage of braking than the brakes any other rail car of the first subset of rail cars. 
     Clause 15: The method of clause 14, further comprising, following step (d): (e) the locomotive processor can provide to each rail car processor of a second subset of the rail cars a braking command that is prepared exclusively for the rail car processor; (f) each rail car processor of the second subset of rail cars can receive the braking command provided to the rail car processor in step (e); (g) each rail car processor of the second subset of rail cars can process the braking command received in step (f); and (h) each rail car processor of the second subset of rail cars can set the brakes of its rail car to a level or percentage of braking included in the braking command processed in step (g) for the rail car processor, whereupon the brakes of each rail car of the second subset of rail cars can be set to the same or a different percentage of braking than the brakes of any other rail car of the second subset of rail cars, wherein the first and second subsets of rail cars can be different. 
     Clause 16: The method of clause 14 or 15, wherein each subset of rail cars can include one or more rail cars. 
     Clause 17: A system for controlling braking of a plurality of rail cars of a train while travelling or moving on a mainline track, the system comprising: a rail car processor associated with each rail car, wherein each rail car processor, operating under the control of a rail car software program, is operative, in response to a unique braking command received by the rail car processor, to set brake(s) of the rail car to a level or percentage commanded by the braking command; a communication network linking the rail car processors of the plurality of rail cars; and a control processor in communication with each rail car processor via the communication network, wherein the control processor, operating under the control of a control software program, is operative for transmitting to each rail car processor the unique braking command prepared exclusively for the rail car processor and which causes the rail car processor to set the brake(s) of the rail car to a level or percentage of braking associated with the unique braking command that is the same or different than a level or percentage of braking of the brake(s) of each other rail car are set. 
     Clause 18: The system of clause 17, wherein: each rail car processor can include a data address that is unique to said rail car processor; and the unique braking command provided to each rail car processor can be addressed to the data address of the rail car processor. 
     Clause 19: A method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, comprising: (a) issuing first and second brake commands to first and second rail cars, wherein the first brake command includes a first level or percentage of braking of the brake(s) of the first rail car, wherein the second brake command includes a second, different level or percentage of braking of the brake(s) of the second rail car; and (b) in response to step (a), setting the brake(s) of the first and second rail cars of the plurality of the rail cars to the respective first and second levels or percentages of braking included in the first and second brake commands. 
     Clause 20: The method of claim  19 , further including, following step (b): (c) issuing third and fourth brake commands to the first and second rail cars, wherein the third brake command can include a third level or percentage of braking of the brake(s) of the first rail car, wherein the fourth brake command can include a fourth level or percentage of braking of the brake(s) of the second rail car that is different than the third level or percentage of braking; and (d), in response to step (c), setting the brake(s) of the first and second rail cars of the plurality of the rail cars to the respective third and fourth levels or percentages of braking included in the third and fourth brake commands. The third and fourth levels or percentages of braking can be different than the first and second levels or percentages of braking. Each of the first through fourth levels or percentages of braking can be different from each other. 
     Clause 21: A method for segmented rail car braking of one or more rail cars of a train while travelling or moving on a mainline track, each rail car equipped with an electronically controllable braking system, the method comprising: (a) identifying one or more groups of one or more rail cars of the train for purposes of braking; and (b) commanding each of the one or more groups of one or more rail cars to brake using a custom braking profile unique to that group in order to achieve a desired overall braking response from the train. 
     Clause 22: The method of clause 21, further comprising defining the custom braking profile for each of the one or more groups of the one or more rail cars based on at least one dynamic behavior of each of the rail cars in each of the one or more groups. In a preferred and non-limiting example, embodiment, or aspect, the dynamic behavior of each rail car can include one or more of the following: rate of change of velocity, G force, pitch or roll behavior, and force on at least one coupler. 
     Clause 23. The method of clause 21 or 22, further comprising defining the custom braking profile to result in a specific dynamic behavior of each of the rail cars in each of the one or more groups. 
     Clause 24. The method of any one of clauses 21-23, further comprising defining the custom braking profile for each of the one or more groups of one or more rail cars based on topology of a track upon which the train is traveling or moving from a present location to a future location located further down the track. In a preferred and non-limiting example, embodiment, or aspect, the topology of the track can include positive track gradient, negative track gradient, track curvature, and track elevation. 
     Clause 25: The method of any one of clauses 21-24, further comprising defining the custom braking profile for each of the one or more groups of one or more rail cars based on a health of a braking system on each of the one or more rail cars in the train. In a preferred and non-limiting example, embodiment, or aspect, the health of the braking system on each car can include wear on the brake discs, wear on the brake shoes, estimated remaining life of the brake discs/shoes, estimated wear based on the cargo carried therein, and estimated wear based on the G forces exerted during the travel. 
     Clause 26: The method of any one of clauses 21-25, further comprising dynamically altering a composition of rail cars in each of the one or more groups based on dynamic response of the train during braking. In a preferred and non-limiting example, embodiment, or aspect, each group may be consecutive rail cars, or discrete rail cars. In a preferred and non-limiting example, embodiment, or aspect, the selection of each group may be made based on desired overall dynamic response of the group as a whole rather than individual rail cars. In a preferred and non-limiting example, embodiment, or aspect, the selection of each group may also be based on individual dynamic response of each rail car. 
     Clause 27: The method of any one of clauses 21-26, wherein steps (a) and (b) are based on a future location of the train selected by a train operator. 
     Clause 28: The method of any one of clauses 21-27, further comprising selecting the future location based on input to a processor, e.g., from a console onboard the train or via a wireless device remote from the train. In a preferred and non-limiting example, embodiment, or aspect, the amount of braking, the number of groups and the number of rail cars in each group to accomplish said amount of braking can be determined by the HEU based on a train speed profile, or distance to braking, or distance to stop based on the selected future location. 
     Clause 29: The method of any one of clauses 21-28, further comprising defining the custom braking profile for each of the one or more groups of one or more rail cars based on environmental conditions in a vicinity of at least one or more rail cars of the train. In a preferred and non-limiting example, embodiment, or aspect, the environmental conditions can include one or more of the following: percent humidity; wind direction; wind speed; the presence (or absence) of rain, ice, or other conditions that can affect traction; track adhesion; and visibility. 
     Clause 30: The method of any one of clauses 21-29, further comprising defining the custom braking profile for each of the one or more groups of one or more rail cars based on physical characteristics of the train. In a preferred and non-limiting example, embodiment, or aspect, the physical characteristics of the train can include one or more of the following for one or more or all of the cars of the train or of the train as a whole: acceleration, deceleration, G forces, pitch or roll behavior, coupler forces, in-car forces, wheel-slip, and wheel-spin. 
     Clause 31. The method of any one of clauses 21-30, further comprising dynamically altering the custom braking profile for each of the rail cars in each of the one or more groups in about real-time. 
     Clause 32. The method of any one of clauses 21-31, further comprising selecting the future location based on input to a navigation equipment onboard the train. In a preferred and non-limiting example, embodiment, or aspect, a train operator can enter the future location, e.g., a destination point, from a GPS console/electronic map. 
     Clause 33. The method of any one of clauses 21-32, further comprising selecting the future location via a wayside dispatching system. 
     Clause 34: A method for braking a train comprising plurality of railcars, the method comprising: identifying a group of one or more railcars that would participate in the braking; providing a specific percentage braking command for each of the one or more railcars; and monitoring braking performance delivered by the braking of the one or more railcars. 
     Clause 35: The method of clause 34, further comprising, performing at least one of the following: altering the specific percentage braking command for each of the one or more railcars participating in the braking; and altering the composition of the group of the one or more railcars by adding a new railcar to the group to participate in the braking, removing an existing railcar from the group of the one or more railcars participating in the braking, or both. 
     Clause 36: The method of clause 34 or 35, further comprising: identifying a second group of one or more railcars that would participate in the braking; providing a specific percentage braking command for each of the one or more railcars of the second group; and monitoring braking performance delivered by the braking of the one or more railcars of the second group. 
     Clause 37: The method of any one of clause 34-36, further comprising performing at least one of the following: altering the specific percentage braking command for each of the one or more railcars of the second group; and altering the composition of the second group of the one or more railcars by adding new railcars to the group to participate in the braking, removing an existing railcar from the group of the one or more railcars participating in the braking, or both. 
     In a preferred and non-limiting example, embodiment, or aspect, the amount of wear of each of one or more brake pads or shoes of a rail car may be visually determined using, for example, a camera that can observe the amount of material left on the brake pad or shoe that can be used. The output of the camera can be processed by the HEU. In a preferred and non-limiting example, embodiment, or aspect, the usable brake material of the brake pad or shoe may be a first color that can be detected by the camera. As the usable brake material wears off, whereupon the brake pad or shoe the requires replacement, the brake material may be a second color. As the color changes, the HEU could know the braking performance may be limited and can alter, e.g., reduce, the percentage of braking provided by the rail car. 
     In a preferred and non-limiting example, embodiment, or aspect, the brake pad or shoe may have multiple colors that can represent more than just two levels of indication of its status. In a preferred and non-limiting example, embodiment, or aspect, the brake pad or shoe may have colors that represent ‘very good’, ‘satisfactory’, ‘needs attention’ and/or ‘needs immediate replacement’ states. 
     In a preferred and non-limiting example, embodiment, or aspect, the brake pad or shoe may include embedded electric/electronic circuitry that can either ‘conduct’ or ‘block’ an electrical signal, e.g., voltage or current. In a preferred and non-limiting example, embodiment, or aspect, continuity of the electrical signal may indicate stable braking material and performance, whereas absence of the electrical signal may indicate a break in the electrical path and therefore a wearing out of the brakes. Multiple electrical paths may be provided to detect different levels of degradation of the brake pad or shoe. 
     In a preferred and non-limiting example, embodiment, or aspect, an improperly configured or misaligned braking system may result in adverse forces on a wheel and/or brake frame of the rail car or braking system. One or more sensors may be provided to detects such adverse forces to indirectly draw an inference of braking system performance. 
     Weather/environmental conditions may be measured at multiple levels. In a preferred and non-limiting example, embodiment, or aspect, the HEU can be pre-programmed with estimated weather conditions at various times of the day for the entire journey along the entire mainline track. This weather data can be gathered from weather sources in any manner, e.g., manually, electronically, e.g., via a wireless network, and entered into the HEU. 
     In a preferred and non-limiting example, embodiment, or aspect, the HEU can be programmed to be updated with local weather events and notifications from the local sources as it travels on the mainline track through the area. These local weather events and notifications can include alerts, such as, for example, flash flood warnings that get beamed to cellphones in a vicinity during heavy rains. 
     In a preferred and non-limiting example, embodiment, or aspect, the HEU can directly receive information about local weather or climatic conditions, including wind patterns, moisture levels, etc. and correlate that information with navigation/terrain information to determine the impact of the weather/climatic conditions on the train and the percentage of braking to be provided by each rail car. In a preferred and non-limiting example, embodiment, or aspect, the train can have means known in the art to measure temperature, wind speed, wind direction, humidity, etc. The HEU can receive the output of such means and can set the percentage of braking of each rail car individually from the percentage of braking of each other rail car from 0% to 100% (or 120% emergency braking) based on said output. 
     Wheel-rail adhesion must be sufficient to fulfil safety and punctuality requirements. In a preferred and non-limiting example, embodiment, or aspect, wheel-rail adhesion is desired during accelerating or braking and less or no wheel-rail adhesion is desired when coasting. During braking, low adhesion can extend the braking distance i.e., increase the distance to reach a particular lower speed, all the way to full stop. Too much or too less wheel-rail adhesion can adversely affect the train&#39;s journey. Further complicating it is the fact that the “proper” wheel-rail adhesion may not always be a fixed value. It can change with changing environmental conditions, geographical location, behavior of the rail cars during braking, the type and nature of cargo being hauled, etc. 
     While traveling or moving on a mainline track, low wheel-rail adhesion can reduce acceleration and extend braking distance, possibly disrupting the travel schedule of the train and possibly other trains that travel on the same track. In a preferred and non-limiting example, embodiment, or aspect, wheel-rail adhesion may be kept low to minimize energy consumption. If the wheel-rail adhesion is too high, the wheels and rails can be subject to excessive shear stress, leading to accelerated wear and surface fatigue. As the wheel-rail contact is an open system, the wheel-rail adhesion can be affected by contaminants. Contaminants, which refers to foreign substances applied both intentionally and unintentionally to the wheel-rail interface, can make wheel-rail adhesion either too high or too low and difficult to predict. The prediction of wheel-rail adhesion can be important not only to railway operation but also to the simulation of multi-body vehicle dynamics. 
     Magnetic sensors are solid state devices that can be used for sensing position, velocity or directional movement. One of the main uses of magnetic sensors is in automotive systems for the sensing of position, distance and speed. For example, the angular position of the crank shaft for the firing angle of the spark plugs, the position of the car seats and seat belts for air-bag control or wheel speed detection for the anti-lock braking system (ABS). Magnetic sensors can respond to a wide range of positive and negative magnetic fields in a variety of different applications and one type of magnet sensor whose output signal is a function of magnetic field density around it is called the Hall Effect Sensor. 
     Hall Effect Sensors are devices which are activated by an external magnetic field. A magnetic field has two important characteristics, namely, flux density, and polarity (North and South Poles). The output signal from a Hall effect sensor is the function of magnetic field density around the device. When the magnetic flux density around the sensor exceeds a certain pre-set threshold, the sensor detects it and generates an output voltage called the Hall Voltage, VH. Hall Effect Sensors are basically comprised of a thin piece of rectangular p-type semiconductor material such as gallium arsenide (GaAs), indium antimonide (InSb) or indium arsenide (InAs) having a continuous current passing therethrough. When the device is placed within a magnetic field, the magnetic flux lines exert a force on the semiconductor material which deflects the charge carriers, electrons and holes, to either side of the semiconductor piece. This movement of charge carriers is a result of the magnetic force the charge carriers experience passing through the semiconductor material. As these electrons and holes move side wards a potential difference is produced between the two sides of the semiconductor material by the build-up of these charge carriers. Then the movement of electrons through the semiconductor material is affected by the presence of an external magnetic field which is at right angles to it and this effect is greater in a flat rectangular shaped material. The effect of generating a measurable voltage by using a magnetic field is called the Hall Effect after Edwin Hall who discovered it back in the 1870&#39;s with the basic physical principle underlying the Hall effect being Lorentz force. To generate a potential difference across the device the magnetic flux lines must be perpendicular, (90°) to the flow of current and be of the correct polarity, generally a south pole. 
     The Hall effect provides information regarding the type of magnetic pole and magnitude of the magnetic field. For example, a south pole would cause the device to produce a voltage output while a north pole would have no effect. Generally, Hall Effect sensors and switches are designed to be in the “OFF”, (open circuit condition) when there is no magnetic field present. They only turn “ON”, (closed circuit condition) when subjected to a magnetic field of sufficient strength and polarity. See e.g., Wolfs et al., “Wheel Speed, Wheel Slip and True Ground Speed Detection Options for Brake Vans”, Centre for Railway Engineering, CRE-R 131 ELEC-2/05, Sep. 21, 2005, which is incorporated herein by reference. 
     Physical measurements of a rail car load may be done at a loading dock. Since the type and quantity of cargo onboard each rail may be known in advance, it can be one of the easier things to determine. In a preferred and non-limiting example, embodiment, or aspect, the rail car may have one or more embedded load cells that can aid in the automatic determination of the rail car load. The output(s) of the one or more embedded load cells can be provided to the HEU which can determined from said output(s) if the rail car is empty, partially full, completely full, or overloaded. In a preferred and non-limiting example, embodiment, or aspect, the output(s) the one or more embedded load cells can be used by the HEU to determine dynamic behavior of cargo in the rail car at various speeds and terrain and inclines and also when subjected to braking forces. How a rail car loaded with solid cargo reacts will be different from how the rail car loaded with a liquid cargo reacts. 
     Rail car weight can range from about 60,000 lbs. (27,215 Kg) empty to about 265,000 lbs. (120,200 Kg) fully laden. The load on each rail car can be measured mechanically using the amount of compression of the springs in the trucks (bogies). For large unit trains, such as trains carrying coal or any kind of ore (using open top rail cars), the tendency is to load each rail car to full load at best, and an overload at worst. Braking systems for rail cars are designed to operate at about peak design load with a +/− safety limit. The behavior of rail cars that are overladen, particularly when travelling at higher speeds on a decline (travelling downhill), can be unpredictable. 
     In a preferred and non-limiting example, embodiment, or aspect, the HEU can monitor a roll behavior of a rail car via one or more load cells sensing forces on the side roller bearing and the side bearing cage of a brake assembly. In a preferred and non-limiting example, embodiment, or aspect, the percent loading on one or more rail cars may be monitored, e.g., optically or via one or more load cells, by the amount of compression of one or more springs of the rail car between a typically minimum and a typical max and an overload threshold. In a preferred and non-limiting example, embodiment, or aspect, by monitoring the percent compression between the truck (bogie) at the front and the back, pitch conditions of the rail car can be determined. In a preferred and non-limiting example, embodiment, or aspect, accelerometers disposed on the rail car may be used to indicate the rate of change and differentiate between a gradual change and an abrupt change. 
     In the U.S., regulations of Federal Railroad Administration of the U.S. Department of Transportation require that the systems of all rail cars of a train operate as expected during normal operations, e.g., while travelling between locations on a mainline track. In a preferred and non-limiting example, embodiment, or aspect, the rail cars of a train can be segmented for the purposes of braking. In a preferred and non-limiting example, embodiment, or aspect, only a select grouping of one or more rail cars and one or more such groups can be used for train braking, while the rest of the rail cars can be operated with their brakes off or not applied. 
     In a preferred and non-limiting example, embodiment, or aspect, all of the rail cars can be used for braking, with the brakes of some of the rail cars commanded to be set to participate more towards the train braking while some of the other rail cars can be commanded to be set to participate less towards the train braking. In this preferred and non-limiting example, embodiment, or aspect, the rail cars that can be commanded to be set to participate less towards the train braking may contribute to braking but with a braking force that may be less than the braking force that would be applied under the S-4200 standard. In a preferred and non-limiting example, embodiment, or aspect, the HEU determines the desired braking effort for the entire train and then delivers desired braking effort using a subset of rail cars. 
     When the brakes of a rail car provide more braking that necessary, e.g., the wheels lock up, it can result in wheel flats. A wheel flat condition is when the running wheels abrade against the steel rail in response to wheel lock up during braking. This results in a wheel flat i.e., a flat surface on the circular surface of the wheels. Apart from wheel flats, the locking of the wheels also results in increased local temperature around the wheel flats. 
     As the train continues travelling or moving on the mainline track, the wheel flats, which will repeatedly contact with the steel rail during each rotation, will increase the amount of shock and vibration experienced by the rail car. Such effects may be measured on the rail car truck (or bogie) and also on the rail car and perhaps even on the cargo carried onboard the rail car. The intensity of the shock and vibration will directly correspond to the extent of the wheel flat or the amount of flatness of the steel wheel. Therefore, one or more sensors (e.g., load cells) measuring shock and vibration can be provided in a rail car to detect a sudden increase in such measurement which can be indicative of a wheel flat. In a preferred and non-limiting example, embodiment, or aspect, the HEU can processes the output of such sensor(s) and can determine therefrom if a wheel on a rail car may have a wheel flat and can adjust (e.g., reduce) a percentage of braking provided to the train by said rail car, e.g., to avoid exasperating the wheel flat condition and/or to avoid fluctuations in the percentage of braking due to the wheel flat repeatedly contacting the rail during braking. 
     In a typical rail car, each brake beam includes two brake heads, each holding a brake shoe. As the brake shoes push against the wheels, there is resultant strain in the brake beam. Using one or more sensors (e.g., load cells) mounted to a brake beam, the degree and orientation of the strain can provide the HEU with a direct indication of the braking force being applied to the wheel. 
     Electrodynamic Energy Harvesting (EEH) operates under Faraday&#39;s law of induction. In a preferred and non-limiting example, embodiment, or aspect, energy is created when a magnetic field passes by an electrically conductive wire or coil. This energy can be captured and converted into a usable current, e.g., in the milli-watt range, which can be used to power low-power devices, such as, for example, sensors and other electronic circuitry, which may be present on one or more rail cars and/or the locomotive of a train, which circuitry may have no connection to a conventional power source, e.g., a battery or a generator. 
     For many of these devices, the 10 mW range may be about the power needed to operate smart-sensors, multi-sensors, nodes and similar devices. Moreover, widely available motion sources of a train can be to drive EEH devices. The most dominant of these excitation sources can include vibration, liquid or air flow, and rotation. Of these sources, for a rail car, vibration offers the greatest potential due to an unlimited amount of excitation sources such as mechanical and environmental vibration, human motion, and wind. 
     However, a drawback of EEH is that the energy generated is only about 4-800 microwatts per cm 3 , which is not near that ideal “10 mW” goal. Initial uses for vibration based EEH involve low-power, non-continuous applications such as television remote controls. 
     In comparison, flow-based electrodynamic energy harvesting typically uses the electrodynamic effect to act as a micro-generator, where the device captures the flow of wind or liquid causing an internal motor to spin and generate energy. The drawback is that most of these harvesters are relatively bulky. The benefit is that the amount of available power generated can be significant, up to 540 mW at 25 liters per minute. 
     Finally, there is rotation-based EEH, which is growing in popularity due to ability to offer high and continuous amounts of motion. Common areas where one might use this form of EEH include cooling fans, internal gears, ventilation systems and existing engines. As for power availability, models of rotation-based EEH have been known to produce above 60 mW of continuous output, provided there is motion. Because of this, there here are numerous theoretical applications for EEH in a train environment as well as the Internet of Things (IoT) which is defined as is the inter-networking of physical devices, vehicles (also referred to as “connected devices” and “smart devices”), buildings, and other items embedded with electronics, software, sensors, actuators, and network connectivity which enable these objects to collect and exchange data. The IoT allows objects to be sensed or controlled remotely across existing network infrastructure, creating opportunities for more direct integration of the physical world into computer-based systems, and resulting in improved efficiency, accuracy and economic benefit in addition to reduced human intervention. When IoT is augmented with sensors and actuators, the technology becomes an instance of the more general class of cyber-physical systems, which also encompasses technologies such as smart grids, virtual power plants, smart homes, intelligent transportation and smart cities. Each thing is uniquely identifiable through its embedded computing system but is able to interoperate within the existing Internet infrastructure. 
     EEH can be broad band, useful in rail cars, for example, where there is plenty of energy that can be harvested from motion of the rail car. Narrow band EEH, which can be more efficient, can be used for more precise and predictable vibration of, for example, electric motors. Information regarding EEH can be found at: http://www.energyharyestingjournal.com/articles/1274/perpetuum-a-vibration-harve sting-company. 
     According to preferred and non-limiting example, embodiment, or aspect, assume a train travelling from location A to location B. Before the train departs from A, accurate information will be known about the following: where is the train headed; how many rail cars; cargo on each of the rail cars; estimated duration of travel to B; existing conditions (traffic related, weather related, work related); existing health condition of the rail cars (i.e., things like brake shoe health, brake system health, rail car health, coupler health). In a preferred and non-limiting example, embodiment, or aspect, this information can be gathered using (IoT). 
     Prior to the present invention, the amount of braking applied on the train is based on the train operator discretion. No two train operators have the same belief in terms of how much braking to apply, when, etc. It&#39;s more an art than a science. 
     In a preferred and non-limiting example, embodiment, or aspect, in accordance with the present invention, the train operator can indicate to the ‘adaptive braking system’ via a human machine interface (HMI) information such as: what is the desired braking requirement (whether to slow down or coast or accelerate); and when is the desired braking condition expected to be reached (e.g., what is the desired speed at a location C, between locations A and B). The ‘adaptive braking system’ can then determine how the total braking requirement of the train can be delivered via braking of a subset of rail cars based on factors such as, without limitation: the health of each brake on each rail car; how much of the brake&#39;s behavior will be impacted by the type/amount of cargo being hauled in each rail car; and/or one or more dynamic characteristics of the moving rail car. 
     In the U.S., regulations require at least 85% of the rail cars in a train to have operating/fully functioning brakes in order for a journey to be initiated. Of course, the ideal condition is that all (100%) of the brakes on all of rail cars are functioning and operational. 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system determines the braking solution for the entire train rather than a braking solution for each rail car. In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system can monitor the dynamic behavior of each rail car and that of the entire train and have the ability to alter an initial group (there can be more than one group) of one or more rail cars with the goal of causing the most stable braking solution for the train such that the desired speed is achieved when the train reaches the desired location B. 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system can initially allocate a subset of rail cars (continuous or discrete/distributed) to participate in the braking solution and then alter the subset of rail cars by adding/removing the number of participating rail cars, desirably in about real-time, and dynamically altering the percent braking required from each of the participating rail cars in about real-time. Other considerations, like health, environment, etc., are merely parameters that are monitored to aid in the adding/removing and altering described above. 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system may determine the gradient of the track as the train proceeds from A to B and determine the braking solution considering the positive impact of gravity (if travel is uphill) or the negative impact of gravity (if travel is downhill). 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system may determine the braking solution based on the adhesion of the wheels to the track (or the lack of it). 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system may determine the braking solution based on weather conditions prevalent in the vicinity of the train based on actual measurement from equipment on the train or remotely via observation from satellites and radar (Doppler, etc.). 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system may determine the braking solution based on curvature of the rail track (super elevation). 
     In a preferred and non-limiting example, embodiment, or aspect, the adaptive braking system may determine the braking solution by requiring all the rail cars to participate in the braking in case of an emergency condition that requires 120% braking. 
     In a preferred and non-limiting example, embodiment, or aspect, in a train having 1 locomotive and 10 rail cars (1-10), the initial braking, based on above criteria, may involve the braking of rail cars 1, 2, 3, 8, 9, and 10. Upon braking, and based on real-time monitoring of dynamic behavior of the train and health of individual subsystem on one or more the rail cars and locomotive, a revised dynamic braking may alter the configuration of the participating rail cars by now requiring rail cars 1, 2, 4, 5, 7, 9 and 10 (3, 8 got dropped while 5, 7 got added). 
     In a preferred and non-limiting example, embodiment, or aspect, if by a certain threshold (time or distance or behavior or combinations), the adaptive braking solution is providing to be insufficient or incapable of slowing the train, the adaptive braking solution can include all the rail cars in the braking solution. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of an example train that includes a locomotive and six rail cars according to the principles of the present invention; 
         FIG. 2  is a schematic illustration of example elements, e.g., a processor or controller and memory, comprising the HEU of the locomotive and the ECP controller of each rail car shown in  FIG. 1 , and including an optional human machine interface (HMI) of the HEU and an optional transmitter for communicating with an optional RF transceiver of the HEU according to the principles of the present invention; 
         FIG. 3  is a schematic illustration of example sources or sensors that can be used individually or in combination and which can communicate data or information to the HEU according to the principles of the present invention; 
         FIG. 4  is an exploded view of a generic bogie according to the principles of the present invention; and 
         FIG. 5  is a flow diagram of an example method of braking in accordance with the principles of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and methods described in the following specification are simply exemplary embodiments, examples, or aspects of the invention. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, in preferred and non-limiting embodiments, examples, or aspects, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the Doctrine of Equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. 
     Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. 
     Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. 
     It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments, examples, or aspects of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments, examples, or aspects disclosed herein are not to be considered as limiting. Certain preferred and non-limiting embodiments, examples, or aspects of the present invention will be described with reference to the accompanying figures where like reference numbers correspond to like or functionally equivalent elements. 
     In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances. Further, in this application, the use of “a” or “an” means “at least one” unless specifically stated otherwise. 
     With reference to  FIG. 1 , a train  14  includes a locomotive  16  and a number of train or rail cars  18 - 1 - 18 -X, where “X” can be any whole number ≥2. In examples discussed hereinafter, train  14  will be described as including six cars  18 - 1 - 18 - 6 . However, this is not to be construed in a limiting sense. 
     Locomotive  16  includes a compressor  20  which operates in a manner known in the art to supply pressurized air to a brake pipe  32  which in turn supplies pressurized air to an air tank  22  in locomotive  16  and in each car  18  in a manner known in the art. The pressurized air stored in each air tank  22  is utilized to control the braking of locomotive  16  and each car  18  of train  14  in a manner known in the art and discussed hereinafter. Locomotive  16  includes an electronically controlled pneumatic (ECP) head-end-unit (HEU)  26 . HEU  26  is coupled via an ECP trainline  28  to an ECP controller  30  in each car  18 . 
     In an example, ECP trainline  28  acts in the nature of a communication network, such as, for example, without limitation, a local area network (LAN), between at least each ECP controller  30  and HEU  26 . More specifically, in response to brake command signals provided by HEU  26  to each ECP controller  30  via trainline  28 , each ECP controller  30  controls the pressure of pressurized air supplied from its air tank  22  to the pneumatic brakes of its car in accordance with the brake command signals, thereby controlling the percent braking of the car  18 . 
     In a conventional ECP braking mode of operation, the brakes of the train are controlled in accordance with the Association of American Railroads (AAR)S-4200 standard braking profile known in the art. In accordance with the S-4200 standard, each ECP controller  30  can be responsive to a single train brake command output by HEU  26  on ECP trainline  28 . For example, in response to HEU  26  outputting a train brake command of, for example, 20% braking on ECP trainline  28 , each ECP controller  30  causes the brakes of its corresponding car  18  to be set to 20% of full braking. In another example, in response to HEU  26  outputting a 50% train brake command (50% braking), each ECP controller  30  causes the brakes of its corresponding car  18  to be set to 50% of full braking. In yet another example, in response to HEU  26  outputting a 100% train brake command (100% braking), each ECP controller  30  causes the brakes of its corresponding car  18  to be set to 100% braking, or full braking. For emergency braking, HEU  26  outputs a 120% train brake command. 
     As can be seen, each ECP controller  30  acts on train brake commands output by HEU  26  in the same manner, namely, the brakes of each car  18  are set to the same percentage of full braking. Hence, in accordance with the S-4200 standard, and except for pneumatic and mechanical variations between the pneumatic brakes of each car  18 , in response to a train brake command output by HEU  26  the brakes of each car  18  respond in the same manner, i.e., the brakes of each car  18  are set to the same percentage of braking as the brakes of each other car  18 . 
     Also, the brakes of locomotive  16  can be controlled in a similar manner by HEU  26 . Namely, in response to outputting a 20%, 50%, or 100% train brake command to ECP trainline  28 , HEU  26  also causes the brakes of locomotive  16  to assume the same percentage of braking as the cars  18  of train  14 . Hence, by way of the S-4200 standard, the brakes of locomotive  16  and each car  18  of train  14  can be set to the same percentage of braking. 
     With reference to  FIG. 2 , in an example, HEU  26  and each ECP controller  30  includes a processor or controller  34  communicatively coupled to ECP trainline  28  and a memory  36  coupled to processor or controller  34  and operative for storing a software control program. For example, the memory  36  of HEU  26  can store a HEU software control program that, when executed by the processor or controller  34  of HEU  26 , implements the S-4200 standard braking profile while the memory  36  of each ECP controller  30  stores an ECP software control program that, when executed by the processor or controller  34  of the ECP controller  30 , implements the ECP controller  30  part of the S-4200 standard braking profile for controlling the braking of the corresponding car  18  in response to train brake commands received by the ECP controller  30  from HEU  26  operating under the control of the first HEU software control program. The HEU software control program stored in memory  36  of HEU  26  is configured to control the operation of the pneumatic brakes of each car  18  via the corresponding ECP controller  30  and to control the brakes of locomotive  16 , all in a manner known in the art. 
     Each memory  36  can include dynamic, volatile memory, e.g., RAM, that loses program code and data stored therein when power to the memory  36  is lost or when overwritten by the corresponding processor or controller  34 , and a non-volatile memory, e.g., ROM, flash memory, and the like, the latter of which (non-volatile memory) can store, at least, an embedded operating system for use by the corresponding HEU  26  or ECP controller  30  in the presence or absence of power applied to the non-volatile memory of the corresponding processor or controller  34 . 
     In normal operation, each ECP controller  30  receives electrical power for its operation via ECP trainline  28 . Each ECP controller  30  can also include a battery  38  that provides electrical power to the corresponding processor or controller  34  and memory  36  in the event power on ECP trainline  28  is lost, e.g., due to a separation of the part of the trainline  28  joining said ECP controller  30  to HEU  26 . 
     HEU  26  receives electrical power for its operation from a battery or generator of locomotive  16 . HEU  26  can also include a battery  38  that provides electrical power to processor or controller  34  and memory  36  of HEU  26  in the event no electrical power is being provided by the battery or generator of locomotive  16   
     During the formation of the train  14 , information regarding the train, including the sequence of cars, locomotives, unique car and locomotive IDs (or data addresses), and other static information parameters regarding train  14  is acquired by HEU  26  and stored in memory  36  thereof. This consist information can include the identification of locomotive  16  and each car  18  of train  14  as well as their positions within train  14 . For example, where train  14  includes a lead locomotive  16  and cars  18 - 1 - 18 - 6  as shown in  FIG. 1 , the consist information can include data identifying locomotive  16  as the first vehicle of the consist; car  18 - 1  as the second car of the consist that is positioned between locomotive  16  and car  18 - 2 ; that car  18 - 2  as the third car of the consist that is positioned between cars  18 - 1  and  18 - 3 ; and so forth including that car  18 - 6  is the final car of the consist. 
     In addition, because ECP trainline  28  acts in the nature of a communication network, such as, for example, without limitation, a local area network (LAN), each ECP controller  30  can have a unique data address that HEU  26  can use to selectively communicate with said ECP controller  30  independent of each other ECP controller  30 . The unique data address of each ECP controller  30  can be preassigned to said ECP controller  30  or can be assigned during the formation of train  14 . In this manner, HEU can selectively address and communicate with one ECP controller  30  independent of each other ECP controller  30 . 
     Having thus described the S-4200 standard and the operation of HEU  26  and each ECP controller  30  to implement the S-4200 standard, a new method of braking in accordance with the principles described herein, which new method of braking is a departure from the S-4200 standard, will now be described with reference to  FIGS. 1 and 2 . 
     In a preferred and non-limiting embodiment, example, or aspect, benefits of this new method of braking can include: optimizing deceleration or stopping of the train; optimizing wear on the brake pads of the brakes of each car  18 ; distributing wear on the brake pads from cars  18  with less brake pad life to cars with more; and the like. 
     In a preferred and non-limiting embodiment, example, or aspect, the new method of braking generally includes a subset (all or less than all) of cars  18  of train  14  participating in braking and, optionally, the percent braking of each participating car. In a preferred and non-limiting embodiment, example, or aspect, the method of braking can occur in about real-time. However, this is not to be construed in a limiting sense. 
     In a preferred and non-limiting embodiment, example, or aspect, with train  14  travelling or moving, for example, on a mainline track, in response to a brake command issued by an operator of train  14 , located for example, in locomotive  16 , in a manner known in the art or herein after developed, HEU  26  can issue a unique braking command, or no braking command, to each ECP controller  30  of a subset of the cars  18  of train  14 . In a preferred and non-limiting embodiment, example, or aspect, the train operator can issue the braking command to HEU  26  via HMI  54  that is part of our coupled to HEU  26 . Herein the unique braking command issued to each ECP controller  30  means that each ECP controller  30  receives a command to set the brakes of its car  18  to a percentage of braking, between 0% and maximum braking, independent of the setting of the brakes of each other car  18 . 
     In a preferred and non-limiting embodiment, example, or aspect, starting from a condition where the brakes of each car  18  are set to 0% braking when train  14  is travelling or moving on a mainline track, HEU  26  can, via ECP trainline  28 , issue unique braking commands to the ECP controllers  30  of each car  18 - 1  through  18 - 6  respectively that cause the brakes of each car  18  to be set, in a preferred and non-limiting embodiment, example, or aspect, as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 2 —25% braking; (3) car  18 - 3 —30% braking; (4) car  18 - 4 —35% braking; (5) car  18 - 5 —40% braking; and (6) car  18 - 6 —45% braking. 
     In a preferred and non-limiting embodiment, example, or aspect, starting from a condition where the brakes of each car  18  are set to 0% braking when train  14  is travelling or moving on a mainline track, HEU  26  can, via ECP trainline  28 , issue unique braking commands to the ECP controller  30  of each car  18 - 1  through  18 - 6  respectively that cause the brakes of each car  18  to be set, in a preferred and non-limiting embodiment, example, or aspect, as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 2 —30% braking; (3) car  18 - 3 —40% braking; (4) car  18 - 4 —30% braking; (5) car  18 - 5 —20% braking; and (6) car  18 - 6 —10% braking. 
     In a preferred and non-limiting embodiment, example, or aspect, starting from a condition where the brakes of each car  18  are set to 0% braking when train  14  is travelling or moving on a mainline track, HEU  26  can, via ECP trainline  28 , issue unique braking commands to the ECP controller  30  of cars  18 - 1 ,  18 - 3 ,  18 - 5 , and  18 - 6  respectively that cause the brakes of these cars to be set, in a preferred and non-limiting embodiment, example, or aspect, as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 3 —25% braking; (3) car  18 - 5 —30% braking; and (4) car  18 - 6 —35% braking. In this example, braking commands were not issued to the ECP controllers  30  of cars  18 - 2  and  18 - 4 , whereupon the brakes of these cars remain at 0% braking. 
     In a preferred and non-limiting embodiment, example, or aspect, starting from a condition where the brakes of each car  18  are set to 0% braking when train  14  is travelling or moving on a mainline track, HEU  26  can, via ECP trainline  28 , issue unique braking commands to the ECP controller  30  of cars  18 - 1 ,  18 - 2 ,  18 - 4 , and  18 - 6  respectively that cause the brakes of these cars to be set, in a preferred and non-limiting embodiment, example, or aspect, as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 2 —25% braking; (3) car  18 - 4 —20% braking; and (4) car  18 - 6 —10% braking. In this example, braking commands were not issued to the ECP controllers  30  of cars  18 - 3  and  18 - 5 , whereupon the brakes of these cars remain at 0% braking. 
     In a preferred and non-limiting embodiment, example, or aspect, when train  14  is travelling or moving on a mainline track and starting from a condition where the brakes of the cars  18  are set as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 2 —0% braking; (3) car  18 - 3 —25% braking; (4) car  18 - 4 —0% braking; (5) car  18 - 5 —30% braking; and (6) car  18 - 6 —35% braking, HEU  26  can, via ECP trainline  28 , issue unique braking commands to the ECP controller  30  of cars  18 - 1 - 18 - 6  respectively that cause the brakes of these cars to be set, in a preferred and non-limiting embodiment, example, or aspect, as follows: (1) car  18 - 1 —20% braking; (2) car  18 - 2 —30% braking; (3) car  18 - 3 —0% braking; (4) car  18 - 4 —30% braking; (5) car  18 - 5 —0% braking; and (4) car  18 - 6 —10% braking. In this example, the braking commands issued by HEU  26  to the ECP controller  30  of cars  18 - 1 - 18 - 6  changed the composition of cars  18  participating in braking, namely, cars  18 - 3  and  18 - 5  were dropped and cars  18 - 2  and  18 - 4  were added. In this preferred and non-limiting embodiment, example, or aspect, viewed differently, the braking commands issued by HEU  26  to the ECP controller  30  of certain cars changed the percent braking of some of the cars while maintaining the same percent braking of other cars. Namely, car  18 - 1  maintained at 20% braking; car  18 - 2  changed from 0% braking to 30% braking; car  18 - 3  changed from 25% braking to 0% braking; car  18 - 4  changed from 0% braking to 10% braking; car  18 - 5  changed from 30% braking to 0% braking; and car  18 - 6 , changed from 35% braking to 10% braking. 
     The various percent brakings described in the above preferred and non-limiting embodiments, examples, or aspects, are for the purpose of illustration only and are not to be construed in a limiting sense since it is envisioned that HEU  26  can selectively set the percent braking on each car  18  in to any suitable and/or desirable percent level independently of the percent level braking of each other car  18  of train  14 . 
     With reference to  FIG. 3  and with continuing reference to  FIGS. 1 and 2 , in a preferred and non-limiting embodiment, example, or aspect, HEU  26  can selectively set the percent braking on each car  18  independently of the percent braking of each other car  18  of train  14  based on input from one or more sources or sensors which can communicate data or information to HEU  26 , directly or indirectly, in any suitable and/or desirable manner. In a preferred and non-limiting embodiment, example, or aspect, these one or more sources or sensors can include one or more or all of the following: 
     one or more electrical/electronic circuits  36 , on each of one or more of the cars  18 , that is designed to conduct or block a signal based on an amount of wear of the material of a brake shoe/pad; 
     one or more optical sensors  38 , e.g., one or more cameras, on each of one or more of the cars  18 , each optical sensor positioned to observe an amount of material remaining on brake pad or brake shoe; 
     a remote transmitter  52  which can transmit weather/environmental conditions to a receiver coupled to or part of HEU  26  via a wired and/or wireless communication link  50  (see  FIG. 2 ); 
     one or more adhesion sensors  40 , on each of one or more of the cars  18 , for measuring track adhesion, wheel slip, and/or wheel skid; 
     one or more load cells  42 , on each of one or more of the cars  18 , for measuring a load carried by the car and/or for measuring dynamic behavior of the car; 
     one or more accelerometers  44 , on each of one or more of the cars  18 , for measuring a rate of change in the dynamic behavior of the car; 
     one or more stain gauges  46 , on each of one or more of the cars  18 , for measuring strain on a brake beam; and 
     one or more accelerometers  44 , on each of one or more of the cars  18 , for measuring a shock and vibration of the car, e.g., to indicate a wheel flat. 
     In a preferred and non-limiting embodiment, example, or aspect, each of the one or more sources  38 - 46  can communicate data or information to HEU  26  via a communication link  48 , which can be separate from or a part of ECP trainline  28 . In a preferred and non-limiting embodiment, example, or aspect, communication link  48  can represent and include processing circuitry, not specifically shown, for processing, as necessary, the output(s) of each of the one or more sources  38 - 46  as needed for use by HEU  26 . In a preferred and non-limiting embodiment, example, or aspect, processing circuitry can include one or more analog-to-digital (A/D) converters for converting analog outputs of sources  38 - 46  into a digital form for processing by HEU  26 . In a preferred and non-limiting embodiment, example, or aspect, although communication link  48  is represented a single line in  FIG. 3 , this is not to be construed in a limiting sense since communication link  48  can be any number of lines that can be used to communicate data and/or information from sources  38 - 46  to HEU  26 . Moreover, in a preferred and non-limiting embodiment, example, or aspect, communication link  48  can be in the nature of, for example, without limitation, a wired and/or wireless network, including a local area network (LAN) which can communicate data and/or information from one or more of sources  38 - 46  to HEU  26 . In a preferred and non-limiting embodiment, example, or aspect, the use of any configuration of wired and/or wireless communication link  48  that enables HEU  26  to receive data and/or information from communication link  48  is envisioned, including, for example, the IoT. 
     Brake Wear: 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can process the output of the each of one or more optical sensors  38  on one or more cars  18  to determine the amount of material remaining on a brake shoe/pad. Based on this determination, HEU  26  can favor braking by cars having more material remaining on its brake shoes or brake pads over cars having brake shoes or brake pads with less material. 
     In a preferred and non-limiting embodiment, example, or aspect, assume cars  18 - 1 ,  18 - 3 , and  18 - 5  are optically determined to each have greater than 75% braking material on the brakes thereof and cars  18 - 2 ,  18 - 4 , and  18 - 6  are optically determined to have greater than 50% braking material on the brakes thereof. In this scenario, for a desired braking requirement for the entire train  14 , HEU  26  can set the brakes of cars  18 - 1 ,  18 - 3 , and  18 - 5  at a greater percentage of braking than the brakes of cars  18 - 2 ,  18 - 4 , and  18 - 6 . Moreover, in this preferred and non-limiting embodiment, example, or aspect, the brakes of each car  18 - 1 ,  18 - 3 , and  18 - 5  can be set to the same and/or different percentage of braking as each other car and the brakes of each car  18 - 2 ,  18 - 4 , and  18 - 6  can be set to the same and/or different percentage of braking as each other car. In other words, each car  18  can be set to a different percentage of braking based on the amount of brake material remaining on one or more brake shoes or brake pads of the car  18 . 
     In a preferred and non-limiting embodiment, example, or aspect, the useable material of a brake shoe/pad can have two or more colors that can be optically detected to determine the material remaining. In a preferred and non-limiting embodiment, example, or aspect, one color may indicate to HEU  26  useable brake material while a second, different color can indicate that the brake shoe/pad requires replacement. In a preferred and non-limiting embodiment, example, or aspect, additional colors can indicate to HEU  26  different levels of brake material, e.g., between greater than 75%, greater than 50%, greater than 25%, and a percentage indicting that the brake shoe/pad requires replacement. 
     In a preferred and non-limiting embodiment, example, or aspect, electrical/electronic circuit  36  can be provided for detecting when there is useable brake material and when the brake material is worn sufficiently such that replacement of the brake material or the brake shoe/pad is required. In a preferred and non-limiting embodiment, example, or aspect, the electrical/electronic circuit can detect the presence or absence of a signal when the brake material is worn sufficiently such that replacement of the brake material or the brake shoe/pad is required. Conversely, the electrical/electronic circuit can detect the other of the presence or absence of a signal when the brake material useable and not worn such that replacement of the brake material or the brake shoe/pad is required. In a preferred and non-limiting embodiment, example, or aspect, the electrical/electronic circuit can also detect one or more additional levels of an amount of useable brake material. Electrical/electronic circuits for electronic brake wear sensing are known in the art and are commercially available. 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can be provided with the output of the electrical/electronic circuit detecting the useable brake material or amount of useable brake material on each car  18  and/or on each brake of each car  18  and can favor braking by cars having more material remaining on its brake shoes or brake pads over cars having brake shoes or brake pads with less material. 
     In a preferred and non-limiting embodiment, example, or aspect, assume that the electrical/electronic circuit determines that the brakes of cars  18 - 1 , and  18 - 2  have greater than 75% braking material, the brakes of cars  18 - 3  and  18 - 4  have about 40% braking material, and the brakes of cars  18 - 5 , and  18 - 6  require replacement of the braking material. In this scenario, for a desired braking requirement for the entire train  14 , HEU  26  can set the brakes of cars  18 - 1  and  18 - 2  to a first percentage of braking e.g., 50% braking, set the brakes of cars  18 - 3  and  18 - 4  to a second percentage of braking, e.g., 30% braking, less than the first percentage of braking, and set the brakes of cars  18 - 5  and  18 - 6  to a third percentage of braking, e.g., 0% braking, less than the second percentage of braking. In a preferred and non-limiting embodiment, example, or aspect, moreover, in this preferred and non-limiting embodiment, example, or aspect, the brakes of one or more of the pair of cars ( 18 - 1 ,  18 - 2 ); ( 18 - 3 ,  18 - 4 ); and ( 18 - 5 ,  18 - 6 ) can be set to different percentages of braking. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to the dynamically changing amount of braking material on each car  18  and/or on each brake of each car  18 . 
     Weather/Environmental Conditions: 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can be provided with weather/environmental conditions. In a preferred and non-limiting embodiment, example, or aspect, the weather/environmental conditions can be provided to HEU  26  in any suitable and/or desirable manner, e.g., manually input via human-machine interface (HMI)  54 , automatically input via receiver  24  receiving the data/information regarding the weather/environmental conditions from remote transmitter  52  via communication link  50 , or the combination thereof. 
     In a preferred and non-limiting embodiment, example, or aspect, the weather/environmental conditions can be input into HEU  26  at any suitable and/or desirable time, e.g., before train  14  departs location A, while train  14  travels on a mainline track through an area, or the combination thereof. In a preferred and non-limiting embodiment, example, or aspect, the weather/environmental conditions can include local weather events and notifications from local, regional, or national sources; information about climate conditions, such as, without limitation, temperature, wind velocity and direction; moisture amounts and types, e.g., snow, rain, sleet, etc.; navigation and terrain information; and the like. In a preferred and non-limiting embodiment, example, or aspect, train  14  can include suitable means to measure weather/environmental conditions can temperature, wind velocity and direction; moisture amounts, and the like, and to input the measured weather/environmental conditions into HEU  26 . In a preferred and non-limiting embodiment, example, or aspect, the weather/environmental conditions input into HEU  26  can include local weather/environmental conditions at the present location of train or any future location of train  14 . 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can use the input weather/environmental conditions to control which cars  18  are used for braking and the percentage of braking by each car used for a desired braking requirement for the entire train  14 . In a preferred and non-limiting embodiment, example, or aspect, in response to snowy conditions input into HEU  26  for the present location of train  14 , HEU  26  can set car  18 - 6  to the highest level or percentage of braking, car  18 - 5  to a percentage of braking between cars  18 - 4  and  18 - 6 , car  18 - 4  to a percentage of braking between cars  18 - 3  and  18 - 5 , and so forth with car  18 - 1  set at the lowest percentage of braking. In a preferred and non-limiting embodiment, example, or aspect, the percent braking by car  18 - 1 - 18 - 6  can be reversed from the prior example with car  18 - 1  providing the highest percentage of braking, car  18 - 6  the lowest highest percentage of braking, and cars  18 - 2 - 18 - 5  providing progressively decreasing percentages of braking. 
     In a preferred and non-limiting embodiment, example, or aspect, the percentage of braking provided by each car  18  can be mixed in any suitable and/or desirable manner to achieve a desired braking requirement for the entire train  14  based on the weather/environmental conditions input into HEU  26 . In a preferred and non-limiting embodiment, example, or aspect, cars  18 - 5  and  18 - 6  can be set to same percentage of braking; cars  18 - 1  and  18 - 2  can be set to same percentage of braking less than cars  18 - 5  and  18 - 6 , and cars  18 - 3  and  18 - 4  can be set to 0% braking. Of course, any other suitable and/or desirable combinations of percentages braking by the cars  18  of train  14  to achieve a desired braking requirement for the entire train  14  are envisioned, including each car have a different percentage of braking between 0% braking and maximum braking. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to changing snow and moisture conditions on the track. 
     Track Adhesion: 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can use the output of one or more adhesion sensors  40  as an indication of track adhesion. Ideally, adhesion between each wheel  56  and the track is wanted during acceleration or braking and not wanted when coasting. During braking, low adhesion can extend the braking distance, e.g., increase the distance to reach a particular lower speed or a full stop in a manner that avoids slippage between the wheel  56  and the mainline track. Too less or too much adhesion can adversely affect the train&#39;s  14  journey. Moreover, an ideal amount or range of adhesion may not be a fixed value. It can change with changing environmental conditions, geographical location, behavior of the rail cars during braking, the type and nature of cargo being hauled, etc. 
     While travelling or moving on a mainline track, low adhesion can reduce train&#39;s  14  acceleration and disrupt the travel schedule of the affected train and other trains in the network. In a preferred and non-limiting embodiment, example, or aspect, adhesion should be low to reduce energy consumption. If adhesion is too high, wheels and rails can be subject to excessive shear stress, leading to additional wear and possibility surface fatigue. 
     As the wheel-rail contact is an open system, adhesion between the wheel and rail can be affected by contaminants. Contaminants, which can be any foreign substance, applied both intentionally and unintentionally, at the wheel-rail interface, can make wheel-rail adhesion either too high or too low and difficult to predict. The prediction of wheel-rail adhesion can be important not only to railway operation but also to the simulation of multi-body vehicle dynamics. 
     In a preferred and non-limiting embodiment, example, or aspect, track adhesion and, more particularly, wheel slip or wheel skid, can be determined by an adhesion sensor based on a difference between a linear speed of a wheel  56  of at least one rail car  18  and a speed (velocity or true ground speed) of train  14  determined in any suitable and/or desirable manner. In a preferred and non-limiting embodiment, example, or aspect, adhesion sensor  40  can be realized by, for example, a magnetic sensor which is one means known in the art for the sensing position, distance and speed of a rotating object, such as a train wheel  56 . Based on the sensed speed of rotation of a wheel  56  by adhesion sensor  40 , a linear speed of the wheel  56  can be determined in a manner known in the art, e.g., ωr: where ω (radians/sec), and r is the wheel radius. Based on any difference between the thus determined linear speed of the wheel  56  and the overall speed of the train determined or sampled at or about the same time, a value of track adhesion, wheel slip, or wheel skid can be determined by HEU  26 , e.g., calculated or from empirical data. In a preferred and non-limiting embodiment, example, or aspect, data regarding track adhesion, wheel slip, or wheel skid for a wheel  56  can be determined by HEU  26  or by a separate processor (not shown) processing the output of the wheel&#39;s  56  adhesion sensor  40 . In a preferred and non-limiting embodiment, example, or aspect, the speed of train  14  can be determined via speed sensor coupled to a reference wheel  56  of train  14 , via a GPS  61  (or other navigation equipment or system) coupled to HEU  26 , via Doppler radar, or any other means. See e.g., Wolfs et al., “Wheel Speed, Wheel Slip and True Ground Speed Detection Options for Brake Vans”, Centre for Railway Engineering, CRE-R 131 ELEC-2/05, Sep. 21, 2005, which is incorporated herein by reference. 
     In a preferred and non-limiting embodiment, example, or aspect, the percentage of braking provided by each car  18  can be mixed in any suitable and/or desirable manner to achieve a desired braking requirement for the entire train  14  based on track adhesion, wheel slip, and/or wheel skid conditions of one or more wheels  56  of train  14  sensed by one or more adhesion sensors. In a preferred and non-limiting embodiment, example, or aspect, data regarding track adhesion, wheel slip, or wheel skid can be processed by HEU  26  to determine the percentage braking to be provided by each car  18  to achieve a desired braking requirement for the entire train  14 . In a preferred and non-limiting embodiment, example, or aspect, if one or both of cars  18 - 3  and  18 - 4  are experiencing low track adhesion, wheel slip, or wheel skid conditions, HEU  26  can set the brakes of one or both of cars  18 - 3  and  18 - 4  to 0% braking, to a low value of braking, e.g., 5% braking or the combination, e.g., 0% and 5% braking, respectively, and can set the brakes of each other car  18 - 1 ,  18 - 2 ,  18 - 5 , and  18 - 6  to a different percentage of braking, e.g., 10%, 20%, 30% and 40% braking, respectively; set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 5 , and  18 - 6  to the same percentage of braking e.g., 25%, or set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 5 , and  18 - 6  to a mixture of the same and different percentages of braking, e.g., 10%, 10%, 30% and 40% braking, respectively. Of course, the use of other suitable and/or desirable combinations of percentage braking by each car  18  when one or more wheels  56  are experiencing low track adhesion, wheel slip, and/or wheel skid conditions to achieve a desired braking requirement for the entire train  14  are envisioned. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to changing track adhesion, wheel slip, and/or wheel skid conditions on the track. 
     Car Loading: 
     Physical load measurements of a loaded car  18  may be done physically at a loading dock. Since the type and quantity of cargo onboard each car may be known in advance, it may be one of the easier things to determine and input into HEU  26 , either manually, via HMI  54 , or via communication link  50 . In a preferred and non-limiting embodiment, example, or aspect, each of one or more cars  18  can have one or more embedded load cells  42  for electronically determining car  18  load which can be communicated to HEU  26  via communication link  48 . In a preferred and non-limiting embodiment, example, or aspect, the physical or electronic load calculation can be optionally used with machine vision as an aid to determining if the car  18  is empty, partially full, completely full, or overloaded. More than just the car load, in a preferred and non-limiting embodiment, example, or aspect, it can be desirable for HEU  26  to develop dynamic behavior of the cargo loaded onboard each of one or more cars  18  at various speeds, terrain, inclines, declines, weather/environmental conditions, when subjected to braking forces. How a car  18  loaded with solid cargo will react will be different from how a car  18  loaded with a liquid cargo will react. 
     Rail car loads often range from about 60,000 lbs. (27,215 Kg) empty to about 265,000 lbs. (120,200 Kg) fully laden. In a preferred and non-limiting embodiment, example, or aspect, the load on each car  18  can be measured mechanically or optically (e.g., a camera) using the amount of compression of the springs in the trucks (bogies). For large unit trains, such as trains carrying coal or ore (using open top rail cars), the tendency is to load to full load at best, and an overload at worst. The braking systems for cars  18  are designed to operate at around the peak load with a +/−a safety limit. The behavior of rail cars  18  that are overladen, particularly when travelling at higher speeds and on an incline or decline, can be unpredictable. 
     In a preferred and non-limiting embodiment, example, or aspect, the roll behavior of a rail car  18  can be monitored via the output(s) of one or more load cells  42  mounted, for example, without limitation, on one or more side roller bearing/side bearing cage arrangements of a bogie. An exploded view of a generic bogie is shown in  FIG. 4 . Side roller bearing/side bearing cage arrangements are known in the art and will not be further described herein. In a preferred and non-limiting embodiment, example, or aspect, the percent loading on a rail car  18  can be monitored by HEU  26  via the one or more load cells  42 , or optically, via one or more optical sensors  38 , determining the percent compression of one or more springs of the car  18  between a typically minimum and a typical max and an overload threshold. In a preferred and non-limiting embodiment, example, or aspect, by monitoring the output of the load cells  42 , percent compression, or any changes thereof, between trucks (bogies) at the front and the back of a car  18 , HEU  26  can determine pitch conditions of the car  18 . In a preferred and non-limiting embodiment, example, or aspect, by monitoring the output of the load cells  42 , percent compression, or any changes thereof between the right and left side of a truck (bogie) of a car  18 , HEU  26  can determine roll conditions of the car  18 . The changing force measured by each load cell  42  can be a direct or indirect measure of the G forces on the car  18 . 
     In a preferred and non-limiting embodiment, example, or aspect, in response to HEU  26  determining based on the output of the load cells  42  in one or more cars  18 , that said car(s)  18  are experiencing undesirable levels of pitch and/or roll, e.g., without limitation, when train  14  is travelling on a curve, an incline, or a decline, HEU  26  can implement a desired braking requirement for the entire train  14  to reduce or eliminate the undesirable levels of pitch and/or roll by setting the brakes of each car  18  to a different percentage of braking or to a mixture of the same and different percentages of braking. In a preferred and non-limiting embodiment, example, or aspect, if HEU  26  determines that car  18 - 3  is experiencing undesirable levels of pitch and/or roll, HEU  26  can set the brakes of car  18 - 3  to 0% or 5% braking to avoid potentially exacerbating the undesirable levels of pitch and/or roll of car  18 - 3 , and can set the brakes of cars  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 5 , and  18 - 6  to 10%, 20%, 30%, 40%, and 50% braking in an attempt to reduce or eliminate the undesirable levels of pitch and/or roll of car  18 - 3 . In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can set the brakes of car  18 - 3  to 0% or 5% braking and can set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 5 , and  18 - 6  to the same percentage of braking e.g., 25%, or can set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 5 , and  18 - 6  to a mixture of the same and different percentages of braking, e.g., 10%, 10%, 30%, 40%, and 50% braking, respectively. Of course, the use of other suitable and/or desirable combinations of percentage braking by each car  18  when one or more cars are experiencing undesirable levels of pitch and/or roll to achieve a desired braking requirement for the entire train  14  that reduces or eliminates the undesirable levels of pitch and/or roll are envisioned. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to changing pitch and/or roll conditions of one or more cars  18 . 
     Coupler Load: 
     Locomotive  16  is joined to car  18 - 1  by a pair of couplers  60  and each pair of cars  18  are joined together by a pair of couplers  60 . A load cell  46  and/or a strain gauge  46  can be coupled to each of one or more of couplers  60  of train  14  to measure in-train forces. In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can, based on the output(s) of these load cell(s)  46  and/or a strain gauge(s)  46 , implement a desired braking requirement for the entire train  14  to reduce an undesirable level of in-train force experienced by one or more of the couplers  60 . In a preferred and non-limiting embodiment, example, or aspect, assume that during a braking event that HEU  26  determines from the output(s) of a load cell  46  and/or strain gauge  26  mounted to one of the couplers  60  between cars  18 - 1  and  18 - 2 , that the in-train forces on said coupler  60  is above a desired level. In this scenario, HEU  26  can dynamically adjust the percentage of braking by each car  18  in a manner that reduces the in-train forces on said coupler. For example, to reduce the in-train forces on the coupler  60 , HEU  26  can reduce the percent braking of car  18 - 1  and can increasing the percent braking of one or more of cars  18 - 2 - 18 - 6 , or vice versa depending on whether the undesirable levels of in-train forces are compression or strain. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to changing level of in-train force experienced by one or more of couplers  60 . 
     Wheel Flat: 
     When the braking system of a car provides more braking that necessary, one or more wheels  56  of one or more cars  18  can lock up, possibly resulting in a wheel flat condition for each affected wheel  56 . A wheel flat condition is when the wheel  56  abrades against the steel rail as the wheel locks up (and doesn&#39;t rotate) during braking. This can result in a wheel flat, i.e., a flat surface on the circular surface of the wheel. Apart from a wheel flat, the locking of the wheel can also result in increased local temperature around the wheel flat. 
     As  14  train continues on its journey, each wheel flat, which will repeat its contact with the steel rail every rotation, can increase the amount of shock and vibration experienced by the car  18 . Such effect can be measured on the truck (bogie) and also on the car  18  and perhaps even on the cargo carried onboard the car  18 . The intensity of the shock and vibration can directly correspond to the intensity of the wheel flat or the amount of flatness of the steel wheel. A measure of the shock and/or vibration and a sudden spike in measurement can indicate a wheel flat. 
     In a preferred and non-limiting embodiment, example, or aspect, one or more load cells  42 , one or more accelerometers  44 , or some combination thereof mounted to a car  18 , e.g., the bogie of a car  18 , can be used to measure shock and/or vibration of the car  18 , which shock and/or vibration can be indicative of a wheel flat condition. In a preferred and non-limiting embodiment, example, or aspect, assume that HEU  26  determines from the one or more load cells  42  and/or the one or more accelerometers  44  that a shock and/or vibration condition exists that indicates or suggests one or more wheels  56  of the car  18  has a wheel flat condition. In this scenario, when it is desired to brake train  14 , HEU  26  can implement a desired braking requirement for the entire train  14  that reduces or eliminates the braking provided by said car  18 . In a preferred and non-limiting embodiment, example, or aspect, if HEU  26  determines that car  18 - 5  has a wheel flat condition, based on detecting undesirable shock and/or vibration, HEU  26  can set the brakes of car  18 - 5  to a lower percent braking than the brakes of the other cars  18  of train  14  to avoid potentially exacerbating the wheel flat condition. 
     In a preferred and non-limiting embodiment, example, or aspect, upon determining that car  18 - 5  may have a wheel flat, HEU  26  can set the brakes of car  18 - 5  to 0% or 5% braking and can set the brakes of cars  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 4 , and  18 - 6  to 10%, 20%, 30%, 40%, and 50% braking. In a preferred and non-limiting embodiment, example, or aspect, upon determining that car  18 - 3  may have a wheel flat, HEU  26  can set the brakes of car  18 - 3  to 0% or 5% braking and can set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 5 , and  18 - 6  to the same percentage of braking e.g., 25%. In a preferred and non-limiting embodiment, example, or aspect, upon determining that car  18 - 5  may have a wheel flat, HEU  26  can set the brakes of each car  18 - 1 ,  18 - 2 ,  18 - 4 ,  18 - 5 , and  18 - 6  to a mixture of the same and different percentages of braking, e.g., 10%, 10%, 30%, 40%, and 50% braking, respectively. Of course, the use of other suitable and/or desirable combinations of percentage braking by each car  18 , when one or more cars are potentially experiencing wheel flat conditions, to achieve a desired braking requirement for the entire train  14  that reduces or avoids potentially exacerbating the wheel flat condition are envisioned. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to a wheel flat condition of one or more cars  18 . 
     Brake Strain: 
     In a typical rail car  18  two brake heads  64 , each holding a brake shoe  66 , are attached to opposite ends of a brake beam  62  (see  FIG. 4 ). As the brake shoes  66  push against the wheels  56 , there is resultant strain in the brake beam  62 . In a preferred and non-limiting embodiment, example, or aspect, each of one or more brake beams  62  on one or more cars  18  can be fitted with a strain-gauge  46 . The degree and orientation of the strain detected by the strain-gauge  46  can provide an indication of the braking force being applied to the wheels  56 . 
     In a preferred and non-limiting embodiment, example, or aspect, one or more strain-gauges  46  can be mounted to one or more brake beams  62  of one or more cars  18 . Each strain-gauge  46  can be used to measure the strain on its brake beam in response to a braking force being applied to the wheels  56  by the brake shoes  66  via the brake heads  64  and can output a signal corresponding to the measured stain. In a preferred and non-limiting embodiment, example, or aspect, a strain-gauge  46  mounted to a brake beam of a fully laden (or overladen) car  18  is expected to measure more strain for a given percentage of braking than when said car  18  is empty. When the car  18  is between fully laden (or overladen) and empty, the stain-gauge  46  is expected, for a given percentage of braking, to measure a level of stain between that measured when the car is fully laden (or overladen) and empty. 
     In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can set the percentage braking by each car  18  based on the output(s) of one or more strain-gauges  46  mounted on the brake beams of one or more cars  18 . In a preferred and non-limiting embodiment, example, or aspect, assume cars  18 - 1  and  18 - 2 , are fully laden with cargo, cars  18 - 3  and  18 - 4  are one-half laden with cargo, and cars  18 - 5  and  18 - 6  are empty (no cargo). In this scenario, if the brakes of each car  18  were set to the same percentage of braking, e.g., 40% braking, the outputs of the strain-gauges  46  of cars  18 - 1  and  18 - 2  would be expected to indicate higher levels of stain that the outputs of the strain-gauges  46  of cars  18 - 3  and  18 - 4 , which would be expected to indicate higher levels of stain that the outputs of the strain-gauges  46  of cars  18 - 5  and  18 - 6 . In a preferred and non-limiting embodiment, example, or aspect, for a desired braking requirement for the entire train  14 , HEU  26  can set the percentage of braking of each car  18  such that the outputs of the strain-gauges  46  are at about the same level ±some predetermined tolerance, e.g., ±5%, 10%, or 15%. In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can set brakes of cars  18 - 1  and  18 - 2  to 20% braking, set the brakes of cars  18 - 3  and  18 - 4  to 30% braking, and set the brakes of cars  18 - 5  and  18 - 6  to 40% to realize the outputs of the strain-gauges  46  being at about the same level ±some tolerance. In this manner, the brake beam of each car can experience about the same level of strain, ±some tolerance related to the ±tolerance of the outputs of the strain-gauges  46 , regardless of cargo load carried by the car. In this manner, HEU  26  is able to dynamically adapt the braking of train  14  in response to stain on the brake beams of one or more cars  18 . 
     Energy Harvesting: 
     Electrical power can be provided to any one or more of the foregoing sources or sensors via a generator of locomotive  16 , one or more batteries  38 , or, in a preferred and non-limiting embodiment, example, or aspect, via one or more energy harvesters mounted to one or more cars  18  or locomotive  16 . Energy harvesters are known in the art as means for converting vibration, the flow of air (wind) or liquid, rotation of a moving part, e.g., a wheel  56  or axle of a car  18 , into electrical energy. Information regarding energy harvesting from vibration normally associated with rail cars can be found at http://www.energyharvestingjournal.com/articles/1274/perpetuum-a-vibration-harvesting-company. 
     In a preferred and non-limiting embodiment, example, or aspect, it is envisioned that any one, or more, or all of the foregoing sources or sensors can be powered by one or more energy harvesters mounted to one or more cars  18  or locomotive  16 . 
     Having thus described sources or sensors, the outputs of which can be used by HEU  26  to set the percentage of braking of each car  18  independently of each other cars to achieve a desired braking requirement for the entire train  14 , an example of the use of one or more of said sources or sensors will now described. 
     In a preferred and non-limiting embodiment, example, or aspect, assume train  14  is travelling on a track from location A to location B. Before leaving location A, the train operator will have accurate information regarding the following: where is the train headed; how many rail cars; cargo and weight of cargo on each of the rail cars; duration of travel to location B; existing conditions (traffic related, weather related, work related); and existing health condition of the rail cars (things like brake shoe health, brake system health, rail car health, coupler health), In a preferred and non-limiting embodiment, example, or aspect, existing health condition of the rail cars can be determined via data enablement (IoT). However, this is not to be construed in a limiting sense. 
     Before the present invention, the amount of braking applied on the train from the locomotive is based on the train operator&#39;s (driver/Engineer-in-Charge) discretion. No two train operators have the same belief in terms of how much braking to apply, when, etc. It&#39;s more an art than a science. 
     In a preferred and non-limiting embodiment, example, or aspect, the train operator can indicate to the ‘adaptive braking system’, via HMI  54 , information such as: what is the desired braking requirement (whether to slow down or coast or accelerate); and when is the desired braking condition expected to be reached (what is the desired speed at a location C). In a preferred and non-limiting embodiment, example, or aspect, based on this input to the HMI  54 , HEU  26  can determined the total braking requirement of the train that can be delivered by setting the percentage of braking of each car  18  independently of each other car based on things like: the health of each brake on each rail car; how much of the brake&#39;s behavior will be impacted by the type/amount of cargo being hauled in each rail car; the impact of the environment on the braking behavior; and the like. 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can set the percentage of braking of each car  18  independently of each other car based on data or information acquired on the present output(s) or about real-time output(s) of one, or more, or all of the foregoing sources or sensors in any suitable and/or desirable manner and/or based on predicated data or information determined from prior data or information acquired from the output(s) of the one or more of the sources or sensors. In the latter scenario, (prior data or information acquired from one or more of the sources or sensors), HEU can be programmed to predict the data or information used by HUE  26  to set the percentage of braking of each car  18  independently of each other in any of the manners described herein. 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can be programmed to consider any one or more or all of the foregoing conditions, e.g., without limitation, brake wear, weather/environmental conditions, track adhesion, car loading, coupler load, wheel flat, and brake stain, when setting the percentage of braking of each car  18  independently of each other car. In a preferred and non-limiting embodiment, example, or aspect, weighting can be used by HEU to favor one or more these conditions over others. The weighting used with each condition can be varied by HEU  26  dynamically during the train&#39;s travel from location A to location B based on conditions encountered by train  14 . For example, when train  14  is travelling in dry conditions on level ground, the weighting used by HEU  26  can favor brake wear over other conditions when setting the percentage of braking of each car  18  independently of each other car. In another example, when train  14  is travelling in snowy or icy conditions in hilly terrain, the weighting used by HEU  26  can favor weather/environmental conditions over other conditions when setting the percentage of braking of each car  18  independently of each other car. 
     In a preferred and non-limiting embodiment, example, or aspect, the weighting used for two or more of these conditions can be blended and modified by HEU  26  in any suitable and/or desirable manner to that allows the percentage of braking of each car  18  to be set independently of each other car to achieve a braking solution or requirement for the entire train rather than a braking solution for each rail car. In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can, via one or more or all of the foregoing sources or sensors on the cars  18 , monitor the dynamic behavior of each rail car and that of the entire train and can alter the percent braking provided by each car of an initial group (there can be more than one group) of one or more rail cars with the objective of causing the most stable braking solution for the train such that a desired speed, or stop, is achieved when the train reaches a location C. 
     With reference to  FIG. 5 , in a method of braking in accordance with the principles described herein, the method initially advances from a start step  80  to a step  82  wherein the percent braking participation by each car of a first subset of cars is set. In a preferred and non-limiting embodiment, example, or aspect, the percent braking participation by each car of the first subset of cars can set independently of the percent braking participation by each other car of the first subset of cars. Next, the method advances to step  84 , wherein the percent braking participation by each car of a second subset of cars is set independently of the percent braking participation by each other car of the second subset of cars. Herein, each subset of cars can include one or more cars and the percent braking participation by each car can be set between 0% braking and full braking. Finally, the method advances to stop step  86 . However, this method is not to be construed in a limiting sense. 
     In a preferred and non-limiting embodiment, example, or aspect, the method advancing to step  84  can be based on changing conditions sensed by sources or sensors, e.g., without limitation, change in brake wear, change in weather/environmental conditions, change in track adhesion, change in car loading, change in coupler load, change in wheel flat, change in brake stain, or a change in any other condition that can affect braking of the train. However, this is not to be construed in a limiting sense since these and any other conditions described herein or known in the art can be monitored and used as an aid changing the percent braking participation by each car. 
     In a preferred and non-limiting embodiment, example, or aspect, HEU  26  may determine the gradient of the track as the train proceeds from A to B and can determine the percent braking participation by each car considering the positive impact of gravity (if travel is uphill) or the negative impact of gravity (if travel is downhill). In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can determine the percent braking participation by each car based on the adhesion of the wheels to the track (or the lack of it). In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can determine the percent braking participation by each car based on weather conditions prevalent in the vicinity of the train based on actual measurement from equipment on the train or remotely via observation from satellites and radar (Doppler, etc.). In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can determine the percent braking participation by each car based on curvature of the rail track (super elevation). In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can determine the percent braking participation by each car by requiring all the rail cars to participate in the braking in case of an emergency condition that requires 120% braking. In a preferred and non-limiting embodiment, example, or aspect, HEU  26  can determine the percent braking participation by each car using any combination of track gradient, wheel adhesion, track curvature, emergency conditions, or any other condition described herein or known in the art. 
     In a preferred and non-limiting embodiment, example, or aspect, HUE  26  can determined the initial percent braking participation by each car based on one or more above conditions, can involve the braking of rail cars  18 - 1 ,  18 - 2 , and  18 - 5 . Upon braking, and based on monitoring of dynamic behavior of the train and health of individual subsystem on each rail car and locomotive, a revised percent braking participation by each car can alter the configuration of the participating rail cars by now requiring braking by rail cars  18 - 1 ,  18 - 3 , and  18 - 4  (cars  18 - 2 ,  18 - 5  were dropped while cars  18 - 3 ,  18 - 4  were added). If, by a certain threshold (time or distance or behavior or combinations), the percent braking participation by each car is proving to be insufficient or incapable of slowing or stopping the train, the percent braking participation by each car can be modified to include additional rail cars or all of the rail cars. 
     As can be seen, disclosed herein is a method of braking a plurality of rail cars of a train while travelling or moving on a mainline track that includes a locomotive processor onboard a locomotive of the train in communication with a rail car processor of each rail car of the train, the method comprising: (a) the locomotive processor providing to each rail car processor of a first subset of the rail cars a unique braking command that is independent of the braking command provided to each other rail car processor of the first subset of rail cars, wherein each braking command includes a level or percentage of braking the brakes of the rail car are to assume; and (b) in response to the braking command provided to each rail car processor of the first subset of the rail cars in step (a), the rail car processor causing the brakes of the rail car to assume the level or percentage of braking included in the unique braking command provided to the rail car processor. In step (a), the unique braking command provided to each rail car processor of the first subset of the rail cars can be provided on or about the same time. 
     In a preferred and non-limiting embodiment, example, or aspect, the unique braking command provided to each rail car processor of the first subset of the rail cars can be based on data regarding the rail car, the train, or both provided to the locomotive processor. 
     In a preferred and non-limiting embodiment, example, or aspect, the data can include predicted or actual data regarding one or more of the following: a health of the braking system of one or more of the rail cars of the train; one or more environmental conditions in a vicinity of the train; dynamic behavior of one or more rail cars of the train while travelling or moving or during braking; topology of a track between a present location and a future location of the train; and a load carried by one or more of the rail cars. 
     In a preferred and non-limiting embodiment, example, or aspect, the data regarding the health of the braking system can include one or more of the following: actual or estimated wear or life of a brake shoe/pad; actual or estimated wear of the brake shoe/pad based on the load carried by one or more of the rail cars of the train; and actual or estimated wear of the brake shoe/pad based on G forces of one or more rail cars of the train while travelling or moving. 
     In a preferred and non-limiting embodiment, example, or aspect, the actual or estimated wear or life of a brake shoe/pad can be determined from optical data of the brake shoe/pad acquired by a camera. 
     In a preferred and non-limiting embodiment, example, or aspect, the one or more environmental conditions can include one or more of the following: temperature, wind speed, wind direction, humidity, the presence or absence of ice or snow on the track upon which the train is travelling, and precipitation. 
     In a preferred and non-limiting embodiment, example, or aspect, the data regarding the one or more environmental conditions can be received wirelessly by the locomotive processor from a source remote from the train. 
     In a preferred and non-limiting embodiment, example, or aspect, the data regarding the dynamic behavior of one or more rail cars of the train while travelling or moving or during braking can include one or more of the following: a force on a coupler; rate of change of velocity (acceleration or deceleration) of the train; G forces of one or more rail cars of the train; pitch or roll of one or more rail cars of the train; and track adhesion determined based on a difference between a linear speed of a wheel of at least one rail car and a speed of the train. 
     In a preferred and non-limiting embodiment, example, or aspect, the data regarding topology can include one or more of the following: track gradient; track curvature; and track elevation. 
     In a preferred and non-limiting embodiment, example, or aspect, the load carried by one of the rail cars of the train can be determined by one or more load cells mounted to the rail car. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further include, following step (b): (c) the locomotive processor providing to each rail car processor of a second subset of the rail cars a unique braking command that is independent of the braking command provided to each other rail car processor of the second subset of rail cars; and (d) in response to the braking command provided to each rail car processor of the second subset of the rail cars in step (c), the rail car processor causing the brakes of the rail car to assume the level or percentage of braking included in the unique braking command provided to the rail car processor, wherein the first and second subsets of rail cars are different. In step (c), the unique braking command provided to each rail car processor of the first subset of the rail cars can be provided on or about the same time. 
     In a preferred and non-limiting embodiment, example, or aspect, step (c) can be based on a changing dynamic response of the first subset of rail cars. In a preferred and non-limiting embodiment, example, or aspect, step (c) can include self-correction or modification of the unique braking commend provided to each rail car to ease the braking forces or require additional braking force based on achieved braking and a desired braking condition for a distance between the present position of the train and a destination point where a desired speed for the train is required in order to safely proceed. The percent braking provided by one or more or all of the cars of the train can be dynamically adjusted and/or reduced as the train decelerates to avoid braking in a manner that causes a sudden lurch of the train, e.g., the overall braking of the train is reduced as the train nears a stopping point or decelerates. In some cases, the destination point may also dynamically change to a different position further down the track or move closer to the train. 
     Also disclosed is a method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, wherein each rail car includes a rail car processor that is operative for controlling the brakes of the rail car, the method comprising: (a) each rail car processor of a first subset of the rail cars receiving a braking command prepared exclusively for the rail car processor; and (b) in response to step (a), each rail car processor of the first subset of the rail cars causing the brakes of its rail car to assume a level or percentage of braking included in the braking command received by the rail car processor in step (a). In step (a), the braking command received by each rail car processor of the first subset of the rail cars can be received on or about the same time. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further include: (c) following step (b), each rail car processor of a second subset of the rail cars receiving a braking command prepared exclusively for the rail car processor; and (d) in response to step (c), each rail car processor of the second subset of the rail cars causing the brakes of its rail car to assume a level or percentage of braking included in the braking command received by the rail car processor in step (c), wherein the first and second subsets of rail cars are different. In step (a), the braking command received by each rail car processor of the second subset of the rail cars can be received on or about the same time. 
     Also disclosed is a method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, comprising: (a) a locomotive processor providing to each rail car processor of a first subset of the rail cars a braking command that is prepared exclusively for the rail car processor; (b) each rail car processor of the first subset of rail cars receiving the braking command provided to the rail car processor in step (a); (c) each rail car processor of the first subset of rail cars processing the braking command received in step (b); and (d) each rail car processor of the first subset of rail cars setting the brakes of its rail car to a level or percentage of braking included in the braking command processed in step (c) for the rail car processor, whereupon the brakes of each rail car of the first subset of rail cars are set to the same or a different percentage of braking than the brakes any other rail car of the first subset of rail cars. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise, following step (d): (e) the locomotive processor providing to each rail car processor of a second subset of the rail cars a braking command that is prepared exclusively for the rail car processor; (f) each rail car processor of the second subset of rail cars receiving the braking command provided to the rail car processor in step (e); (g) each rail car processor of the second subset of rail cars processing the braking command received in step (f); and (h) each rail car processor of the second subset of rail cars setting the brakes of its rail car to a level or percentage of braking included in the braking command processed in step (g) for the rail car processor, whereupon the brakes of each rail car of the second subset of rail cars are set to the same or a different percentage of braking than the brakes any other rail car of the first subset of rail cars, wherein the first and second subsets of rail cars are different. 
     In a preferred and non-limiting embodiment, example, or aspect, each subset of rail cars can include one or more rail cars. 
     Also disclosed is system for controlling braking of a plurality of rail cars of a train while travelling or moving on a mainline track, the system comprising: a rail car processor associated with each rail car, wherein each rail car processor, operating under the control of a rail car software program, is operative, in response to a unique braking command received by the rail car processor, to set brake(s) of the rail car to a level or percentage commanded by the braking command; a communication network linking the rail car processors of the plurality of rail cars; and a control processor in communication with each rail car processor via the communication network, wherein the control processor, operating under the control of a control software program, is operative for transmitting to each rail car processor the unique braking command prepared exclusively for the rail car processor and which causes the rail car processor to set the brake(s) of the rail car to a level or percentage of braking associated with the unique braking command that is the same or different than a level or percentage of braking of the brake(s) of each other rail car are set. 
     In a preferred and non-limiting embodiment, example, or aspect, each rail car processor can include a data address that is unique to said rail car processor; and the unique braking command provided to each rail car processor is addressed to the data address of the rail car processor. 
     Also disclosed is a method of braking a plurality of rail cars of a train while travelling or moving on a mainline track, comprising: (a) issuing first and second brake commands to first and second rail cars, wherein the first brake command includes a first level or percentage of braking of the brake(s) of the first rail car, wherein the second brake command includes a second, different level or percentage of braking of the brake(s) of the second rail car; and (b) in response to step (a), setting the brake(s) of the first and second rail cars of the plurality of the rail cars to the respective first and second levels or percentages of braking included in the first and second brake commands. In a preferred and non-limiting embodiment, example, or aspect, the first and second levels or percentages of braking can be different. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further include, following step (b): (c) issuing third and fourth brake commands to the first and second rail cars, wherein the third brake command includes a third level or percentage of braking of the brake(s) of the first rail car, wherein the fourth brake command includes a fourth level or percentage of braking of the brake(s) of the second rail car that is different than the third level or percentage of braking; and (d) in response to step (c), setting the brake(s) of the first and second rail cars of the plurality of the rail cars to the respective third and fourth levels or percentages of braking included in the third and fourth brake commands. In a preferred and non-limiting embodiment, example, or aspect, the third and fourth levels or percentages of braking can be different. 
     Also disclosed is a method for segmented rail car braking of one or more rail cars of a train while travelling or moving on a mainline track, wherein each rail car is equipped with an electronically controllable braking system, the method comprising: (a) identifying one or more groups of one or more rail cars from the train for purposes of braking; and (b) commanding each of the one or more groups of one or more rail cars to brake using a custom braking profile unique to that group in order to achieve a desired overall braking response from the train. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile for each of the one or more groups of the one or more rail cars based on at least one dynamic behavior of each of the rail cars in each of the one or more groups. In a preferred and non-limiting example, embodiment, or aspect, the dynamic behavior of each rail car can include one or more of the following: rate of change of velocity, G force, pitch or roll behavior, and force on at least one coupler. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile to result in a specific dynamic behavior of each of the rail cars in each of the one or more groups. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile for each of the one or more groups of one or more rail cars based on topology of a track upon which the train is of a traveling or moving from a present location to a future location located further down the track. In a preferred and non-limiting example, embodiment, or aspect, the topology of the track can include positive track gradient, negative track gradient, track curvature, and track elevation. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile for each of the one or more groups of one or more rail cars based on a health of a braking system on each of the one or more rail cars in the train. In a preferred and non-limiting example, embodiment, or aspect, the health of the braking system on each car can include wear on the brake discs, wear on the brake shoes, estimated remaining life of the brake discs/shoes, estimated wear based on the cargo carried therein, and estimated wear based on the G forces exerted during the travel. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise dynamically altering a composition of rail cars in each of the one or more groups based on dynamic response of the train during braking. In a preferred and non-limiting example, embodiment, or aspect, the groups may be consecutive rail cars, or discrete rail cars. In a preferred and non-limiting example, embodiment, or aspect, the selection of each group may be made based on desired overall dynamic response of the group as a whole rather than individual rail cars. In a preferred and non-limiting example, embodiment, or aspect, the selection of each group may also be based on individual dynamic response of each rail car. 
     In a preferred and non-limiting embodiment, example, or aspect, steps (a) and (b) can be based on a future location of the train selected by a train operator. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise selecting the future location based on input from a console onboard the train or via a wireless device remote from the train. In a preferred and non-limiting example, embodiment, or aspect, the amount of braking, the number of groups and the number of rail cars in each group to accomplish said amount of braking can be determined by the HEU based on a train speed profile, or distance for braking, or distance to stop based on the selected future location. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile for each of the one or more groups of one or more rail cars based on environmental conditions in a vicinity of at least one or more rail cars in the train. In a preferred and non-limiting example, embodiment, or aspect, the environmental conditions can include, without limitation, one or more of the following: percent humidity; wind direction; wind speed; the presence (or absence) of rain, ice, and conditions that affect traction; track adhesion; and visibility. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise defining the custom braking profile for each of the one or more groups of one or more rail cars based on physical characteristics of the train. In a preferred and non-limiting example, embodiment, or aspect, the physical characteristics of the train can include one or more of the following: acceleration, deceleration, G forces, pitch or roll behavior, coupler forces, in-car forces, wheel-slip, and wheel-spin. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise dynamically altering the custom braking profile for each of the rail cars in each of the one or more groups in about real-time. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise selecting the future location based on input to a navigation equipment onboard the train. In a preferred and non-limiting example, embodiment, or aspect, a train operator can enter the future location, e.g., a destination point, from a GPS console/electronic map. 
     In a preferred and non-limiting embodiment, example, or aspect, the method can further comprise selecting the future location via a wayside dispatching system. 
     In a preferred and non-limiting embodiment, example, or aspect, as the train continues to decelerate, the dynamic response of the groups of rail cars may change. In a preferred and non-limiting embodiment, example, or aspect, this can require a self-correction or modification of the custom braking profiles such that it can ease the braking forces or require additional braking force based on achieved braking and distance to comply. Distance to comply may be the distance between present position of the train and the destination point where a desired speed for the train is required in order to safely proceed. The distance to comply can continuously reduce as the train travels. In some cases, the destination point may also dynamically change to a different position further down the track or move closer to the train. 
     In a preferred and non-limiting embodiment, example, or aspect, one or more processor or controller  34  described herein can be a microprocessor. Also or alternatively, one or more processor or controller  34  can be implemented using special purpose circuitry, with or without software, such as a Application-Specific Integrated Circuit (ASIC) or Field-Programmable Gate Array (FPGA). In a preferred and non-limiting embodiment, example, or aspect, one or more processor or controller  34  described herein can be implemented using hardwired circuitry without software, or in combination with software. Thus, the foregoing description is limited neither to any specific combination of hardware circuitry and software, nor to any particular source for the software executed by the processor or controller  34 . 
     Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical preferred and non-limiting embodiments, examples, or aspects, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed preferred and non-limiting embodiments, examples, or aspects, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any preferred and non-limiting embodiment, example, or aspect can be combined with one or more features of any other preferred and non-limiting embodiment, example, or aspect.