Abstract:
A system for automatically performing a bail off of the locomotive brakes in response to certain train braking operations without the need for the train operator to manually bail off the locomotive brakes. The system includes a controller that is programmed to determine when an appropriate train braking operation has been requested and to issue commands to the locomotive braking system to cause the locomotive brake cylinder to be reduced to zero pressure or a predetermined minimum pressure. The controller is also programmed to determine when an automatic bail off should be inhibited and/or cancelled depending on ongoing train conditions.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to locomotive braking systems and, more particular, to an automatic bail off during brake applications. 
         [0003]    2. Description of the Related Art 
         [0004]    A locomotive operator using a pneumatic or electro-pneumatic braking system is required to make a reduction in the brake pipe (BP) pressure to apply the train brakes. Due to operating rules or conditions of train control, the locomotive operator may have to perform a bail off that prevents the locomotive brake cylinders from applying while a reduction in brake pipe pressure is made to apply the train brakes. Generally, the term bail off is used to refer to the removal of pressure from the brake cylinders of a locomotive or multiple locomotives in a consist. 
         [0005]    To accomplish the application of the train brakes and a bail off of the locomotive brakes, the locomotive operator must perform two operations simultaneously, which typically requires the use of both hands on the equipment that allows the operator to apply the train brakes while preventing the locomotive brake cylinders from applying. A locomotive operator has, however, many other demands on his or her attention in situations where the train brake are being applied. The act of bailing off the locomotive brakes must happen regardless of the situation and therefore is an added activity that can distract from other decisions and actions that the locomotive operator must perform, such as determining the appropriate amount of brake pipe reduction to be made, deciding whether dynamic braking should be applied, etc. Similar decisions and operations must also be made in electronically controlled pneumatic (ECP) brake control systems with respect to the train brake command (TBC) communication level and the resulting effect on the locomotive brake cylinder pressure. Accordingly, there is a need in art for a system that can reduce the level of input needed from the locomotive operator to bail off the locomotive brakes during a train braking event. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The invention comprises a system for automatically bailing off a train having a locomotive braking system with at least one locomotive brake cylinder. 
         [0007]    The system includes a controller programmed to determine when an operator of the train has initiated a brake application and to send a bail off command to the locomotive braking system that results in a release of a predetermined amount of pressure from at least one locomotive brake cylinder. The controller may be integrated with or coupled to a conventional train braking system, which has a locomotive operator input with a train brake handle and an independent brake handle, and is interconnected to the rail car braking system and locomotive braking system. The locomotive braking system responds to the bail off command sent by the controller by releasing the predetermined amount of pressure from at least one locomotive brake cylinder. 
         [0008]    In one approach, the controller is programmed to determine whether the operator of the train performed a manual bail off of the locomotive braking system in connection with a prior train brake application and to enable the sending of the bail off command only if the operator of the train performed the manual bail off. The controller is further programmed to send the bail off command if the operator of the train performed a manual bail off of the locomotive braking system in connection with a prior train brake application and the operator of the train subsequently initiates another brake application. The controller is also programmed to determine whether the operator of the train has requested a subsequent brake application beyond the equivalent of a full service brake and, if so, to send a command cancelling the bail off. 
         [0009]    In another approach, the controller is programmed to determine whether the operator of the train has initiated a brake application between a minimum service brake application and a full service brake application and to send the bail off command if the brake application is between a minimum service brake application and a full service brake application. The controller is also programmed to determine whether the operator of the train has requested a subsequent brake application beyond the equivalent of a full service brake and, if so, to send a command cancelling the bail off. 
         [0010]    In a further approach, the controller is programmed to determine whether there is an end of train signal and to only send a bail off command if there is an end of train signal. 
         [0011]    In an additional approach, the controller is programmed to determine if the locomotive is in lead cut-in prior to sending a bail off command. The controller is also programmed to determine that locomotive is not in an emergency state prior to sending a bail off command. The controller is further programmed to determine that the locomotive is not in a penalty state prior to sending a bail off command. 
         [0012]    The controller may be programmed to perform any one of or all of the various approaches to performing an automatic bail off, thereby relieving the operator of the responsibility to manually input the train braking command into a first manual input as well as manually performing a bail off of the locomotive brakes using a second manual input. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0013]    The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  is a schematic of a system for automatically providing a bail off of the locomotive brakes during a train brake application according to the present invention; 
           [0015]      FIG. 2  is flowchart of a bail off process for a system for automatically providing a bail off of the locomotive brakes during a train brake application according to the present invention; 
           [0016]      FIG. 3  is flowchart of another bail off process for a system for automatically providing a bail off of the locomotive brakes during a train brake application according to the present invention 
           [0017]      FIG. 4  is flowchart of a further bail off process for a system for automatically providing a bail off of the locomotive brakes during a train brake application according to the present invention; 
           [0018]      FIG. 5  is flowchart of an additional bail off process for a system for automatically providing a bail off of the locomotive brakes during a train brake application according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in  FIG. 1  a system  10  for automatically providing a bail off of the locomotive brakes during a train brake application, referred to herein as an automatic bail off operation. More particularly, system  10  comprises an automatic bail off controller  12 , which may be provided by programming the existing programmable elements of train braking system  14  of a locomotive  16  or by providing controller  12  as a separate module that is interfaced with train braking system  14 , such as by interconnecting controller  12  to a network bus such as those typically included with the electronic brake valve and processor of an electronically controlled train braking system  14 . Train braking system  14  is interconnected to a locomotive operator braking input  18 , which can include a train brake handle  20  as well as an independent brake handle  22 . Train braking system  14  is also interconnected to the locomotive braking system  24  and the rail car braking system  26 . 
         [0020]    Regardless of whether controller  12  is integrated into train braking system  16  or provided as a separate module, controller  12  is programmed to perform certain decision-making procedures in response to receiving an input from the locomotive operator via input  18  as well as other braking system conditions and, when appropriate, issues the appropriate commands to locomotive braking system  24  to perform a bail off of the locomotive brakes without any additional manual inputs from the locomotive operator, such as the operator having to physically move independent brake handle  22 . The commands sent by controller  12  may comprise a signal such as an independent actuating and release (IA &amp; R) pressure, an electrical signal, or a communication signal sent through a serial communication port or a train network, that cause locomotive braking system  24  to bail off the locomotive brakes during a train braking operation. The automatic bail off operation can be configured to result in a complete exhausting of the locomotive brake cylinder pressure to zero pounds per square inch (psi) or to a predetermined minimum locomotive brake cylinder pressure, such as 10 psi, that is sufficient to minimize train run-in during a train brake application while still allowing the locomotive braking system to provide some braking force to the train. The automatic bail off operation may also be configured to operate in conjunction with locomotive braking system  24  to initially bail off to a zero psi pressure level in the locomotive brake cylinders and then gradually increase the locomotive brake cylinder pressure over a predetermined time period and at a predetermined rate to eliminate train run-in during the initial brake application while minimizing the train stopping distance by restoring the locomotive brakes to a level that helps brake the mass of the locomotive(s) after the train brake application has had time to propagate through the entire train. The predetermined time period and predetermined rate may be determined based on factors such as the particular composition of the train, the requirements of the applicable governmental safety regulations, or customer preferences. 
         [0021]    As seen in  FIG. 2 , system  10  may be configured to implement a bail off process  30  wherein controller  12  is programmed to initiate an automatic bail off operation based on prior manual braking applications performed by the locomotive operator. For example, once a brake application has been initiated by the train operator  32 , controller  12  is programmed to perform a check  34  to determine whether a bail off operation was manually made in combination with a prior train brake application that was initiated by the operator. If so, controller  12  is enabled to perform an automatic bail off operation during the next train brake application  36 . If a subsequent check  38  determines that a brake application has been initiated by the locomotive operator, controller  12  sends a bail off command  40  to locomotive braking system  24  to perform a bail off operation without any additional input from the locomotive operator. The bail off command may be configured to initiate a bail off operation for a predetermined time period, such as a default pre-established by the owner of system  10 . Alternatively, the predetermined time period may be adjusted dynamically based on the amount of brake pipe reduction made by the operator, the size of the locomotive consist, or a target locomotive brake cylinder pressure. Finally, a check  42  is performed to determine whether the operator has changed the braking requirement, such as by moving the brake handle beyond the “full service” position or to another predetermined position and, if so, a command is sent by controller  12  to locomotive braking system  24  to cancel the bail off  44 . 
         [0022]    As seen in  FIG. 3 , system  10  may be configured to implement another bail off process  50  wherein controller  12  is programmed to send a command initiating an automatic bail off operation in response to any manual brake application between “minimum” and “full service” that is requested by the locomotive operator. Thus, after a brake application has been initiated by the operator  52 , a check  54  is performed to determine whether the operator has moved the train brake handle between the “minimum” and “full service” positions (or any other defined positions). If so, automatic bail off operations are enabled  56  and a command is sent to locomotive braking system  24  to perform a bail off operation  58  without any additional input from the locomotive operator. A check  60  is then performed to determine whether the operator has changed the braking requirement, such as by moving the brake handle beyond the “full service” position or to another predetermined position and, if so, the bail off is cancelled such as by controller  12  sending a command cancelling the bail off  62 . In this process  50 , as with other embodiments, the locomotive operator has the option at any time of manually performing a bail off procedure using the independent brake lever or executing an emergency brake application, which would be identified by check  60  and result in a cancelling of the automatic bail off operation. 
         [0023]    As seen in  FIG. 4 , system  10  may be configured to implement a further bail off process  70  that determines whether there are freight cars attached to the locomotive or locomotive consist to mitigate the safety risk of a light locomotive. After a brake application has been initiated  72 , a check  74  is performed of the end of train (EOT) brake pipe pressure signal available from the EOT in the locomotive to determine whether there is an EOT brake pipe pressure. If there is not any EOT brake pipe pressure, automatic bail off of controller  12  is disabled  76 . If there is EOT brake pipe pressure at check  74 , controller  12  is enabled  78  to send a command initiating an automatic bail off procedure and a command is send  80 . In lieu of EOT brake pipe pressure, several other data items may be used as the triggering condition at check  74 , such as a confirmed EOT communications address, an EOT heartbeat signal, or an EOT GPS signal, may be used as an EOT signal that allows controller  12  to enable the automatic bail function. As before, a check  82  may be made to determine whether the brake requirement has changed and, if so, a command sent to cancel the bail-off  84 . 
         [0024]    As seen in  FIG. 5 , controller  12  may be programmed to implement a process  90  where automatic bail off operations are enabled in response to an operator input to the locomotive driver&#39;s interface display or a momentary switch on the operative driver&#39;s control stand. First, automatic bail off operation is manually enabled by the operator  92 . For safety, controller  12  is programmed to disable automatic bail off operation if a check  94  determines that the locomotive is not in lead cut-in, a check  96  determines that the locomotive is in an emergency state, or a check  98  determines that the locomotive is in a penalty brake state. In the event that controller  12  has disabled automatic bail off operation because of checks  94 ,  96 , or  98 , the operator must re-enable the function by manually enabling automatic bail off operations  92 . If checks  94 ,  96 , or  98  pass, and a brake application is subsequently initiated by the operator  100 , controller  12  sends a command to perform a bail off  102 . If a check  104  determines that the brake requirement has changed, a command cancelling the bail off is sent  106 . If any of checks  94 ,  96 , or  97  are negative, automatic bail-off operation is disabled  108 . 
         [0025]    As seen in  FIG. 6 , processes  30 ,  50 ,  70 , and  80  may be implemented simultaneously or made available in a single system  10  that allows for an automatic bail off operation to be enabled or disabled according to default settings, operator input, or the conditions of locomotive braking system. Thus, the controller may be programmed to perform any one of or all of the various approaches to performing an automatic bail off, thereby relieving the operator of the responsibility to manually input the train braking command into a first manual input as well as manually performing a bail off of the locomotive brakes using a second manual input.