Abstract:
A train consist for freight transportation includes a first or lead locomotive and at least one second or trail, adjacent locomotive directly connected with one another, followed by a plurality of cars or wagons. 
     Each of the locomotives has an Electronically Controlled Pneumatic Brake System (ECPBS), a brake handle installed in the driver&#39;s cab providing electric signals to control the ECPBSs upon train operator&#39;s commands, and a communication layer used to transmit various signals between the two or more adjacent locomotives of the consist. 
     The electrical signals generated by the brake handle in the lead locomotive are extended to at least the first trail locomotive through the communication layer in order to control the ECPBS in the trail locomotive, providing full train brake redundancy, allowing non-degraded train operation even in case of an unrecoverable failure of the brake control system in the lead locomotive.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to pneumatic braking systems for railway trains, and in particular to pneumatic braking systems for locomotive consists. 
     A train consist for freight transportation includes at least first and second adjacent locomotives, directly connected with each other, followed by a plurality of interconnected cars or wagons. The very first locomotive of such a consist is named the lead locomotive, whereas the at least one further locomotive of the consist is named a trail locomotive. 
     In modern trains for freight transportation each locomotive of such a consist is provided with an Electronically Controlled Pneumatic Brake System (hereinafter referred to as the ECPBS) and a brake control handle device installed in the driver&#39;s cab provides electric control signals to the ECPBS in accordance with the commands by the train driver. 
     The current state of the art in American freight railways operation, despite the coming introduction of the new ECP (Electronically Controlled Pneumatic) technology and the long lasting Radio Distributed Power technology (the Locotrol” system of “General Electric”), is still mostly based on train consists formed of multiple adjacent locomotives pulling a plurality of connected cars, wherein the whole train braking effort is exclusively managed by the ECPBS of the lead locomotive, controlling the pressure in the brake pipe extending through the whole train consist, according to the electric signals from the brake handle of the lead locomotive. According to the pressure variations, the pneumatic brake system of each wagon or car will individually apply a retardation effort contributing to brake, slow down and stop the whole train. 
     In case of a critical failure occurring in the ECPBS in the lead locomotive, the whole train can result unable to properly brake, requiring procedures and actions to rescue the train, or to replace the failing lead locomotive with an efficient one, for instance by exchanging the positions of the lead and the trail locomotives. 
     SUMMARY OF THE INVENTION 
     The present invention generally relates to:
         a railway electronically-controlled pneumatic brake system, ECPBS, controlling the pressure in the brake pipe extending along a train consist;   a lead locomotive brake handle, providing brake commands as electrical signals, coupled to the ECPBSs of the lead locomotive and of at least the first trail locomotive of the consist, through a communication layer extending through at least the first two locomotives in the train consist; and   a method for individually enabling/disabling the ECPBSs in the lead locomotive and in at least the first trail locomotive, said ECPBSs being connected to the lead locomotive brake handle through a communication link to control the braking pressure in the brake pipe according to electrical signals from the brake handle of the lead locomotive.       

     In a train consist according to the present invention, in case of a critical failure occurring to the ECPBS in the lead locomotive, signals provided by the brake handle of the lead locomotive can be extended to the ECPBS of the first adjacent trail locomotive, through a communication link extending through at least the first two adjacent locomotives of the consist, either by using spare pins on an already available AAR Multi-Unit (hereinafter MU) connector, or by using power line technology over MU pins, or by using a dedicated custom connector. 
     In this way, the pneumatic brake system of the adjacent trail locomotive, still controlled through the electric signals from the brake handle in the lead locomotive, will take over control from the failing ECPBS of the lead locomotive, allowing the train to reach the end of service without major inconveniences to the operation thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present invention will become apparent from the following description of embodiments, provided with reference to the annexed drawings, wherein: 
         FIG. 1  is a diagrammatic representation of a train including a train consist formed of a lead locomotive and one trail locomotive; 
         FIG. 2  is a block diagram showing the structure of an ECPBS according to the prior art; 
         FIG. 3  shows the structure of another ECPBS according to the prior art; 
         FIG. 4  is a block diagram showing a structure of an ECPBS for use in a train consist according to the present invention; 
         FIG. 5  is a block diagram showing an enhanced variant of embodiment of the ECPBS of  FIG. 4 ; 
         FIG. 6  shows another variant of embodiment of the ECPBS of  FIG. 4 ; 
         FIG. 7  shows an improved variant of the ECPBS of  FIG. 6 ; 
         FIG. 8  is a block diagram of an embodiment of a brake control handle device suited for use with the systems of  FIGS. 5 and 7 ; and 
         FIG. 9  shows a variant of embodiment of the brake control handle device of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a conventional train consist  101  formed of two adjacent locomotives  102  and  103  pulling a plurality of wagons  150 . 
     Lead locomotive  102  delivers pneumatic brake commands to trail locomotive  103  through a brake pipe and Multiple Unit commands through MU connectors  106  and a cable  105 . 
     The lead locomotive  102  is that from which the train operator controls the operational modes of the whole train consist  101 . In particular, from the lead locomotive  102  the train operator controls the brake operational modes of the whole train consist  101 . 
     According to the present invention, a general locomotive braking architecture and related possible implementations are disclosed, allowing the train operator to operate the train brake operational modes by using the brake handle of the lead locomotive, which is able to control either the brake system installed on the lead locomotive  102  or the brake system installed on the trail locomotive  103 , selecting which of the two brake systems is to be activated, depending upon the “health” status of the lead locomotive brake system. 
       FIG. 2  shows an example of current state of the art ECPBS, comprising a pneumatic manifold  201 , on which one or more pneumatic components  202  (such as, for example, relay valves, check valves, triple valves or distributor valves), electro-pneumatic actuators  203  (such as, for example, solenoid valves and proportional solenoid valves), and sensors  204  (such as, for example, pressure switches and pressure transducers) are installed, and controlled by a stand-alone electronic control unit (ECU)  205  through cables  206  wired in any of possible different fashions. 
     The pneumatic manifold  201  is connected to brake cylinders, a brake pipe and an equalizing pipe, through piping connections  207 . 
     The stand-alone electronic control unit  205  receives brake commands through electrical cables  208  from brake handle  209 . 
     The signals flowing through electrical cables  208  can be of analog type (such as, for example, currents of 4-20 mA), encoded digital type signals, Pulse-Width-Modulation type signals, Data-Communication type signals (such as, for example, CAN, or Echelon, or RS485, or Ethernet signals). 
     A single failure, for instance in the stand-alone electronic control unit  205 , or in the electrical cable  208 , can irreparably prevent the ECPBS from properly controlling the pressure in the brake pipe, causing the train operation to stop and requiring rescue. 
       FIG. 3  shows an example of current state of the art ECPBS, comprising a pneumatic manifold  301 , on which one or more pneumatic components  302  (such as, for example, relay valves, check valves, triple valves or distributor valves) and electro-pneumatic modules  303  controlled by integrated electronic units  304  (such as, for example, mecha-tronic or pneuma-tronic line replaceable units) are installed. 
     The pneumatic manifold  301  is connected to brake cylinders, the brake pipe and an equalizing pipe, through piping connections  305 . 
     A brake control handle device  306  sends brake commands via electrical cables  307  to an electronic interface module  308  (such as, for example, a gateway, or a junction-box, or a bridge) which forwards brake commands to the integrated electronic units of modules  304  via electrical cables  309 . 
     The signals flowing through electrical cables  307  can be of analog type (such as, for instance, currents of 4-20 mA), encoded digital type signals, Pulse-Width-Modulation type signals, or data-communication type signals (such as, for example, CAN signals, Echelon signals, RS485 signals, Ethernet signals). 
     Also the signals flowing through electrical cables  309  can be a combination of analog signals, encoded digital signals, Pulse-Width-Modulation type signals and data-communication signals. 
     According to various solutions, the electronic interface module  308  can be installed on the brake manifold  301 , or can be stand-alone. 
     A single failure, for example in the electronic interface module  308  or the electrical cable  307 , can irreparably prevent the ECPBS from properly controlling the pressure in the brake pipe(s), causing the train operation to stop and requiring rescue. 
     Embodiment of  FIG. 4   
       FIG. 4  shows a Multiple Unit Brake System architecture for a train consist according to the present invention, including:
         at least two adjacent locomotives, i.e. lead locomotive  402  and trail locomotive  403 ;   lead locomotive brake apparatus, comprising a brake control handle device  401  and a related enable/disable device  406 , and an Electronically Controlled Pneumatic Brake System (ECPBS)  410 ;   trail locomotive brake apparatus, comprising a brake control handle device  412  and a related enable/disable device  413 , and an Electronically Controlled Pneumatic Brake System (ECPBS)  411 ;   braking pipes  418 ; and   a communication layer, including communication links  415  and  416 , locomotive brake interfaces (LBI)  404  and  409  and a locomotive interconnection cable  408 .       

     Electrical commands from the brake control handle device  401  can reach the ECPBS  411  through said communication layer: the train operator can control the brake pipe pressure from the brake handle  401  of the lead locomotive, by controlling the ECPBS  411 , should the ECPBS  410  in the lead locomotive irreparably fail. 
     With the architecture shown in  FIG. 4  the brake handle  401  available on the lead locomotive  402  physically forwards brake commands to the ECPBS  410  of the lead locomotive and the locomotive brake interface  404 , through the communication link  415  (which is, for example, a LON network, or a CAN network, or an encoded digital signal network or an analog signal network). 
     The enable/disable device  406  (such as a switch) is used to enable or disable the brake handle  401  to selectively allow or prevent it from delivering brake commands on the communication link  415 . 
     The locomotive brake interface  404  is a device in charge of transferring the brake commands from the lead locomotive  402  to the trail locomotive  403  through the locomotive interconnection cable  408 . 
     In the trail locomotive  403  the locomotive brake interface  409  receives brake commands through the locomotive interconnection cable  408  and transfers such brake commands to the communication link  416 . 
     The communication link  416  transfers the brake commands to the ECPBS  411 . A brake control handle device  412  is connected to the communication link  416 . An enable/disable device  413 , such as a switch, is used to enable or disable the brake handle  412  in the trail locomotive  403 , to selectively allow or prevent it from delivering brake commands to the communication link  416 . 
     In the lead locomotive  401  an active/cut-out device  431  is used to enable or disable the ECPBS  410  to react to the brake commands issued over the communication link  415 . 
     Similarly, in the trail locomotive  403  an active/cut-out device  432  is used to enable or disable the ECPBS  411  to react to brake commands received through the communication link  416 . 
     In the lead locomotive  402  one or more pneumatic devices  433  (such as, for example, pneumatic cocks or pneumatic valves) are used to connect or isolate the brake manifold  434  from one or more brake pneumatic pipes  418 , such as, for example, a brake pipe, a brake balance pipe and an additional pneumatic pipe  13 . 
     In the trail locomotive  403  one or more pneumatic devices  435 , such as for example pneumatic cocks or pneumatic valves, are used to connect or isolate the brake manifold  436  from the pneumatic brake pipes  418 . 
     A Man-Machine Interface (MMI)  421 , comprising for instance a display or a screen, is connected to the communication link  415  to show information related to the ECPBSs  410  and  411 , such as brake commands and/or diagnostic information received from the ECPBSs  410  and  411 . A similar MMI  422  is provided on board the trail locomotive  403 . 
     Normal Operation 
     According to the present invention and with reference to the architecture shown in  FIG. 4 , when the ECPBS  410  in the lead locomotive  402  is fully operable and exempt from any failures that could prevent the train consist from properly operating, the enable/disable device  406  is set to enable the brake handle  401  to deliver brake commands over the communication link  415 , and the active/cut-out device  431  is set to enable the ECPBS  410  to operate in accordance with the brake commands issued by the brake handle  401  over the communication link  415 . The pneumatic devices  435  are set in the condition in which they couple the brake manifold  434  to the pneumatic pipes  418  allowing the ECPBS  410  to properly control the braking pressure corresponding to the commands issued from the brake handle  401 . 
     The enable/disable device  431  is instead set to disable the brake handle  412  in the trail locomotive, which is prevented from delivering brake commands over the communication link  416 ; the active/cut-out device  432  is set to disable the ECPBS  411 , preventing it from operating upon brake commands received over the communication link  416 . The pneumatic devices  435  are set in the condition in which they isolate the brake manifold  436  from the pneumatic brake pipes  418 , preventing the ECPBS  411  from influencing the pressures in the pneumatic brake pipes  418 . 
     Man-Machine Interface  421  in the lead locomotive  402  displays functional and diagnostic information from the ECPBS  410  and diagnostic/health information received from the ECPBS  411  through communication link  416 , locomotive brake interface  409 , locomotive interface cable  408 , locomotive brake interface  404  and communication link  415 . 
     Failure Mode Operation 
     With reference to the architecture shown in  FIG. 4 , when the ECPBS  410  in the lead locomotive  402  is affected by one or more failures preventing the train consist from properly operating, the enable/disable device  406  is set to enable the brake handle  401  to deliver brake commands over the communication link  415 , and the active/cut-out device  431  is set to disable the ECPBS  410  preventing it from operating upon brake commands issued by the brake handle  401  over the communication link  415 ; the pneumatic devices  433  are set in the condition in which they isolate the brake manifold  434  from the brake pneumatic pipes  418 , preventing the ECPBS  410  from influencing the pressures in said pneumatic pipes  418 . 
     The enable/disable device  413  in the trail locomotive  403  is set to disable the brake handle  412 , preventing it from delivering brake commands over the communication link  416 . The active cut-out device  432  is set to enable the ECPBS  411  to operate according to brake commands received over the communication link  416 ; the pneumatic devices  435  are set in the condition in which they connect the brake manifold  436  to the brake pipes  418 , allowing the ECPBS  411  to control the pressures in said pipes  418  in accordance with the brake commands received from the brake handle  401  of the lead locomotive  402  through the communication link  415 , the locomotive brake interface  404 , the locomotive interconnection cable  408 , the locomotive brake interface  409  and the communication link  416 . 
     Man-Machine Interface  421  in the lead locomotive  402  displace diagnostic/health information received from the ECPBS  410  and functional and diagnostic information from the ECPBS  411  through communication link  416 , locomotive brake interface  415 , locomotive interface cable  408 , locomotive brake interface  404  and communication link  415 . 
     Embodiment of  FIG. 5   
       FIG. 5  shows an enhanced variant of the brake system shown in  FIG. 4 : the communication link between the brake handle  501  and the ECPBS  510  is made redundant by adding a communication link  520  in parallel to link  515 . 
     Compared with  FIG. 4 , when a failure on the communication link  415  would prevent the train operator from controlling both the ECPBSs  410  and  411 , the architecture shown in  FIG. 5  allows the train operator to control the ECPBS  510  even if communication link  515  is in irreparable, permanent failure. In summary, the architecture shown in  FIG. 5  provides the train consist with full electro-pneumatic brake redundancy up to the level of the brake handle  501 . 
     In the variant shown in  FIG. 5  the brake handle  501 , available in the lead locomotive  502 , physically forwards brake commands to the ECPBS  510  in the lead locomotive and to the locomotive brake interface  504  through communication link  515 . In addition, the brake handle  501  forwards redundant brake commands to the ECPBS  510  of the lead locomotive through the additional communication link  520 , which is for example a LON network, or a CAN network, or an encoded digital signal network, or an analog signal network. An enable/disable device  506 , such as a switch, is used to enable or disable the brake handle  501 , allowing or preventing it from delivering brake commands on both the communication links  515  and  520 . Thus, the redundancy of communication links  515  and  520  allows the brake command delivery from brake handle  501  to ECPBS  510  to be single-fault tolerant. 
     Embodiment of  FIG. 6   
       FIG. 6  shows an adaptation of the architecture of  FIG. 4  for the case in which a locomotive communication network is available in the locomotive consist. Such a locomotive communication network can be available to connect intelligent modules  630  (such as, for example, bus administrators, MMIs, traction control modules, event recorders, etc.) and comprises communication links  615  and  616 , locomotive communication interfaces  604  and  609  and locomotive interconnection cable  608 . 
     The brake handle  601  can forward brake commands to the ECPBS  611  in the trail locomotive  603  through said locomotive communication network. Adaptation and synchronization of the protocol of the communication links  615  and  616  to the locomotive communication network protocol is performed by train gateways  621  and  612 . 
     The communication layer in  FIG. 6  comprises communication links  615  and  616 , train gateways  621  and  622 , locomotive communication interfaces  604  and  609 , and locomotive interconnection cable  608 . 
     According to the architecture shown in  FIG. 6 , like in  FIG. 4  the train operator can control the braking pipe pressures from the brake handle  601  in the lead locomotive, by controlling the ECPBS  611 , should the ECPBS  610  in the lead locomotive irreparably fail. 
       FIG. 6  shows the lead locomotive  602  provided with a locomotive data bus  615 . The locomotive data bus  615  is in charge of interfacing the on board intelligent modules  630 . 
     The locomotive data bus  615  is coupled to the locomotive data bus  616  in the trail locomotive  603 , through locomotive communication interfaces  604  and  609  and inter-car bus connection  608 . 
     According to the present invention, in the architecture shown in  FIG. 6  the brake handle  601  in the lead locomotive  602  physically forwards brake commands to the ECPBS  610  of the lead locomotive, and to the train gateway  621 , through a communication link  615   a.    
     An enable/disable device  606  is used to enable or disable the brake handle  601 , allowing or preventing it from delivering brake commands on the communication link  615   a.    
     The train gateway  621  transfers to brake commands generated by the brake handle  601  from the communication link  615   a  to the locomotive data bus  615  according to the related existing communication protocol. In such a way the brake commands will be issued to the train gateway  622  in the trail locomotive  603  through the locomotive communication interfaces  604  and  609 , the inter-car bus connection  608  and the locomotive data bus  615 , according to the prevailing communication protocol. 
     The train gateway  622  transfers the brake commands from the locomotive data bus  616  to a communication link  616   a.    
     In the trail locomotive  603  a brake handle  612  is connected to the communication link  616   a . An enable/disable device  613  is used to allow or prevent the brake handle  612  to deliver brake commands on the communication link  616   a.    
     In the lead locomotive  602  an active cut-out device  631  is used to enable or disable the ECPBS  610  to perform the brake commands issued over the communication link  615   a.    
     Similarly, in the trail locomotive  603  an active cut-out device  632  is used to enable or disable the ECPBS  611  to perform the brake commands received through the communication link  616   a.    
     In the lead locomotive  603  one or more pneumatic devices, such as pneumatic cocks or pneumatic valves, are used to connect or isolate the brake manifold  634  from one of more brake pneumatic pipes  618 . 
     In the trail locomotive  603  one or more pneumatic devices  635  are similarly used to connect or isolate the brake manifold  636  from one or more of the brake pneumatic pipes  618 . 
     Still with reference to  FIG. 6 , when the ECPBS  610  in the lead locomotive  602  is fully operable, exempt from failures that could prevent the train consist from properly operating, the enable/disable device  606  is set to enable the brake handle  601  to deliver brake commands over the communication link  615   a , the active cut-out device is set to enable the ECPBS  610  to operate upon brake commands issued by the brake handle  601  over the communication link  615   a ; the pneumatic devices  633  are set in the condition in which they connect the brake manifold  634  to the brake pneumatic pipes  618  allowing the ECPBS  610  to properly control the braking pressures corresponding to brake commands issued by the brake handle  601 , and the enable/disable device  613  is set to disable the brake handle  612  to prevent it from delivering brake commands over the communication link  616   a ; the active cut-out device  632  is set to disable the ECPBS  611 , preventing it from operating upon brake commands received over the communication links  616   a ; the pneumatic devices  635  are set in the condition in which they isolate the brake manifold  636  from the brake pneumatic pipes  618 , preventing the ECPBS  611  from influencing the pressures in said pipes  618 . 
     According to the present invention, and as shown in  FIG. 6 , when the ECPBS  610  in the lead locomotive  602  is affected by one or more failures which prevent the train consist from properly operating, the enable/disable device  606  is set to enable the brake handle  601  to deliver brake commands over the communication link  615   a , and the active cut-out device  631  is set to disable the ECPBS  610  preventing it from operating according to the brake commands issued from the brake handle  601  over the communication link  615   a ; the pneumatic devices  633  are set in the condition in which they isolate the brake manifold  634  from the brake pneumatic pipes  618 , preventing the ECPBS  610  from influencing the pressures in said pipes. In the trail locomotive  603  the enable/disable device  612  is set to disable the brake handle  612  preventing it from delivering brake commands over the communication link  616   a ; the active cut-out device  632  is set to enable the ECPBS  611  to operate according to brake commands received over the communication link  616   a ; the pneumatic devices  635  are set in the condition in which they connect the brake manifold  636  to the brake pneumatic pipes  618 , allowing the ECPBS  611  to control the pressures in the brake pneumatic pipes  618  according to the brake commands received from the brake handle  601  through the communication link  615   a , the train gateway  621 , the locomotive data bus  615 , the locomotive communication interface  604 , the inter-car connection  608 , the locomotive communication interface  609 , the locomotive data bus  616 , the train gateway  622  and the communication link  616   a.    
     Embodiment of  FIG. 7   
       FIG. 7  shows an enhancement of the system shown in  FIG. 6 : in the lead locomotive  702  the communication link between the brake handle  701  and the ECPBS  710  is made redundant by adding a communication link  715   b  in parallel to the communication link  715   a . Compared with  FIG. 6 , when a failure in the communication link  615   a  would prevent the train operator from controlling both the ECPBSs  610  and  611 , the architecture shown in  FIG. 7  allows the train operator to control the ECPBS  711  even in case communication link  715   a  is in irreparable permanent failure. In summary, the architecture shown in  FIG. 7  provides the train consist with full electro-pneumatic brake redundancy up to brake handle  701 . 
     According to the invention, in the variant shown in  FIG. 7  the brake handle  701  in the lead locomotive  702  physically forwards brake commands to the ECPBS  710  and train gateway  721  through two independent communication links  715   a  and  715   b . The redundancy of communication links  715   a  and  715   b  allows the brake command delivery from brake handle  701  to ECPBS  710  to be single-fault tolerant. 
     Brake Handle Design 
     The control architecture shown in  FIG. 5  involves using a brake handle  501  capable of providing brake commands on independent communication links  515  and  520 . Also the control architecture shown in  FIG. 7  involves using a brake handle  701  capable of providing brake commands on independent communication links  715   a  and  715   b.    
       FIG. 8  shows a possible implementation of a brake handle suitable to furthermore improve the redundancy provided by the architectures shown in  FIGS. 5 and 7 . 
     According to  FIG. 8  a brake handle  501 / 701  includes an electromechanical arrangement  808 , wherein a lever  801  is mechanically coupled through a shaft  803  with an angular position sensor or encoder  802 , such as a potentiometer or an optical encoder or a magnetic encoder. The angular encoder  802  is connected to two independent electronic modules  804  and  805  through an electrical connection  806 . 
     The electronic modules  804  and  805  are predisposed to convert the electrical signals provided by the encoder  802  into proper brake commands to be issued on the communication links  515 ,  520  or  715   a ,  715   b.    
     Each of the electronic modules  804  and  805  can convert the signals from more than one angular encoder, for instance also the signals from an additional angular encoder  809 , should the brake handle be provided with more than one operating lever, such as the additional lever indicated  810  in  FIG. 8 . 
     Auxiliary functional switches  811  can be provided in the brake handle, connected to the electronic modules  804  and  815 . 
     The electronic modules  804  and  815  are coupled to respective connectors  807  and  808 , which are coupled with the corresponding communication links connected to the brake handle. 
       FIG. 9  shows an enhancement of the brake handle device described with reference to  FIG. 8 . 
     In the variant of  FIG. 9  brake control lever  901  is coupled to two angular encoders  902 ,  902   a  through a same shaft  903 . The encoders  902 ,  902   a  are respectively connected to independent electronic modules  905 ,  906 , which are coupled to respective electrical connectors  907 ,  908 . 
     If the brake handle is provided with more than one operating lever, for instance also with an additional lever  910 , the same encoder redundancy is reproduced also for the additional lever  910 , which is thus provided with angular encoders  909 ,  909   a.    
     The variant of  FIG. 9  provides complete electronic redundancy, so that the resulting brake handle is single-fault redundant.