Abstract:
A train including a brake pipe ( 14 ) and an electrical train line ( 50 ) extending from at least one locomotive through at least first and second cars which are adjacent to each other, the first and second cars each include a brake cylinder, reservoir and a brake valve The first car includes an electro-pneumatic brake valve which is responsive to electric signals on the train line to produce a first car pneumatic apply brake signal from the first reservoir and release brake signal for the first brake cylinder and the brake signal pipe ( 33 ) The first car also includes a first valve ( 31 ) to transmit the first brake signals to the brake signal pipe and to isolate the connection to the brake signal pipe for a breakaway at one of the cars The second car includes a pneumatic brake control valve which is responsive to the first car pneumatic brake signals on the brake signal pipe and brake pipe pressure m the brake pipe to produce a second car pneumatic apply and release brake signals for the second brake cylinder corresponding to the first apply and release brake signals The pneumatic brake control valve also produces a second car pneumatic apply brake signal from the second reservoir for an emergency pressure in the brake pipe and no brake signal on the brake signal pipe.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of and incorporates herein by reference provisional application Ser. No. 60/679,653 filed May 11, 2005. 
     
    
     BACKGROUND AND SUMMARY OF THE DISCLOSURE 
       [0002]    The present invention relates generally to brake systems for trains, and more specifically, to a brake system for trains having a mixture of electro-pneumatic (EP) brake valves and pneumatic brake valves on different cars. 
         [0003]    In the U.S. and other countries which use the standard of the American Association of Railroads (“AAR”), railroads have been studying and implementing electro-pneumatic brake valves in the individual cars. Not all railroads are capable of or want a complete train with electro-pneumatic brake valves. Some railroads prefer to have a mixture of electro-pneumatic brake valve cars with pneumatic brake valve cars. In an electro-pneumatic train, the brake pipe is maintained at its full value and the electrical signals provided to the electro-pneumatic valves produce a pneumatic braking on the EP cars. Since the brake pipe is always at its full value or release, the pneumatic brake valve cars have to be controlled by an adjacent electro-pneumatic car. This will be accomplished by a separate brake signal pipe which connects the electro-pneumatic car to the adjacent pneumatic car. A problem arises if this brake signal pipe is disconnected, as is the brake pipe. One or both of the cars may not be able to automatically apply their brakes in response to a breakaway. This is especially critical to the last car on the train since it is not connected to any other car which may be capable of bringing that segment of the train to a stop. 
         [0004]    One solution to the problem is providing a special electro-pneumatic last car which would be designed not to be connected to a brake signal pipe. For some railroads, the dedication of a special end car may not be convenient or desirable. 
         [0005]    The present disclosure is directed to a train including a brake pipe and an electrical train line extending from at least one locomotive through at least first and second cars which are adjacent to each other and connected by a brake signal pipe. The first car includes a first brake cylinder, a first reservoir and an electro-pneumatic brake valve. The electro-pneumatic brake valve is responsive to electric signals on the train line to produce a first car pneumatic apply brake signal from the first reservoir and release brake signal for the first brake cylinder and the brake signal pipe. The first car also includes a first valve to transmit the first brake signals to the brake signal pipe and to isolate the connection to the brake signal pipe for a breakaway at one of the cars. The second car includes a second brake cylinder, a second reservoir, and a pneumatic brake control valve. The pneumatic brake control valve is responsive to the first car pneumatic brake signals on the brake signal pipe and brake pipe pressure in the brake pipe to produce a second car pneumatic apply and release brake signals for the second brake cylinder corresponding to the first apply and release brake signals. The pneumatic brake control valve also produces a second car pneumatic apply brake signal from the second reservoir for an emergency pressure in the brake pipe and no brake signal on the brake signal pipe. 
         [0006]    This system allows both cars to apply their brakes for a brake-way condition no matter where they are in the train. 
         [0007]    These and other aspects of the present method will become apparent from the following detailed description of the method, when considered in conjunction with accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a schematic of a married pair of cars having one car with an electro-pneumatic brake and a second car with a pneumatic brake in its most general terms according to the present disclosure. 
           [0009]      FIG. 2  is a first embodiment of the married pair of cars with a standalone EP brake valve according to the present disclosure. 
           [0010]      FIG. 3  is a second embodiment of the married pair of cars with a standalone EP brake valve according to the present disclosure. 
           [0011]      FIG. 4  is a third embodiment of a married pair of cars with an overlay EP brake valve according to the present disclosure. 
           [0012]      FIG. 5  is a fourth embodiment of a married pair of cars with an overlay EP brake valve according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]      FIG. 1  shows an electro-pneumatic car (EP car) and a pneumatic car (P-car) as a married pair of cars. The married pair of cars is part of a train which includes a brake pipe  14  extending through the train and coupled together by couplers or glad-hands  15 . It also includes a train line  50  with junction boxes  52  and couplers  53  to receive power and control signals for the electro-pneumatic brake valves. The EP car includes a pipe bracket  30  with an EP brake valve  40  and a vent valve  54 . The details of the EP brake valve are described in U.S. Pat. No. 6,457,782 which is incorporated herein by reference. Such an EP valve is available from New York Air Brake as an EP 60 , but other equivalent EP brake valves may be used. The numbers used in the drawings will generally correspond to that in U.S. Pat. No. 6,457,782. Wherever possible such a reference will be made thereto for the details. The EP portion  40  is connected through junction box  48  to the train line  50 . The box  48  includes a car ID. 
         [0014]    The brake pipe  14  is connected through a cut-off cock  12  to port  1  of the pipe bracket  30 . A reservoir  22  is shown as a combined reservoir having an emergency and an auxiliary section connected to ports  2  and  5 , respectfully. Port  3  of the pipe bracket  30  is connected to an empty load device  26  having its own reservoir  25 . The output signal of the empty load device  26  is connected to the brake cylinders  24 . Although a pair of brake cylinders is shown, a single brake cylinder may be provided on the EP car. The structure described so far is that of a standard EP car. Pipe bracket  30  is a standard pipe bracket for pneumatic or EP brake valves. 
         [0015]    Also connected to port  3  is a valve  31  connecting the pneumatic brake signal to the brake signal pipe  33 , which interconnects the EP car and the P car. Valve  31  is responsive to reservoir pressure or pneumatic signal to close the connection between the P car and the brake signal pipe  33 . In  FIG. 1 , the valve  31  is shown as a two-way valve which is spring biased to its disconnect or closed position and is piloted to its connect or open position by the pressure in the emergency reservoir at port  2  of the pipe bracket  30 . For all brake apply or release, brake cylinder pressure is applied and released through the pipe bracket port  3  to brake signal pipe  33 . Once the emergency reservoir is reduced to a given value, for example, 40 psi, the spring will overcome the pilot pressure and disconnect port  3  from the brake signal pipe  33 . This will isolate and allow the brake cylinders  24  to maintain a brake apply condition even though the brake signal pipe  33  has been vented as has the brake pipe  14 . 
         [0016]    The pneumatic P car includes a pneumatic brake control valve PBCV  60  connected to the brake pipe  14 , the brake signal pipe  33 , reservoir  22  and brake cylinder  24 . The pneumatic brake control valve  60  is responsive to the first EP car brake signals on the brake signal pipe  33  and the brake pipe pressure on brake pipe  14  to produce second car pneumatic apply and release brake signals for the brake cylinder  24  of the second car. The second car&#39;s pneumatic apply and release signals correspond to the apply and release brake signals received from the brake signal pipe  33 . For an emergency pressure on the brake pipe  14 , the pneumatic brake control valve  60  produces the car pneumatic apply brake signal from the reservoir  22  to its cylinder  24 , as long as the brake signal pipe  33  is also vented to zero. The pneumatic brake control valve  60  also includes a disconnect of the brake signal pipe  33  in response to an emergency pressure in the brake pipe  14 . 
         [0017]    Even though  FIGS. 1 through 3  show a standalone electro-pneumatic brake in the EP car and  FIGS. 4 and 5  show an overlay electro-pneumatic brake in the EP, either style or type of EP brake valve may be used in  FIGS. 1  though  5 . The different drawings show different implementations of the pneumatic brake control valve  60  as well as the valve  31 . 
         [0018]    The first embodiment of the pneumatic brake control valve  60  is illustrated in  FIG. 2 . A standard pneumatic brake valve including pipe bracket  30  and a service portion  10  and an emergency portion  20  is shown. This may be, for example, a DB  60  available from New York Air Brake Corporation or its equivalent. The brake pipe  14  is connected to the manifold  30  by cut-of cock  12 . The combined reservoir  22  is also connected to the pipe bracket  30 . The brake signal output at port  3  of the pipe bracket  30  is connected to a select or piloted three-way valve  62 . The three-way valve  62  is spring-biased into the shown position where the brake signal output port  3  is connected to the empty load relay  26  and the VTA empty load valve  23 . The relay valve  26  provides a brake signal to the brake cylinders  24  from a reservoir  25  which is charged from the pipe bracket  30  through charging check valve  27 . 
         [0019]    The shown position of valve  62  is the emergency position when there is a break-in-two. This cuts off the connection of the empty load relay valve  26  from the open brake signal pipe. A connection is made from port  3  of the pipe bracket  30  to port  8  of the E/L relay  26 . This maintains the brakes  24  applied in the P car. 
         [0020]    Three-way valve  62  is biased to its second position connecting the brake signal pipe  33  to the empty load relay valve  26  by a pilot pressure from a double check valve  66  connected by a choke  68  to a volume  70  to the pilot port of valve  62 . The double check valve  66  selects the higher of the two inputs as the pilot signal. Connected to the double check valve  66  are the brake pipe  14  on one side and the brake signal pipe  33  on the other side. 
         [0021]    Normally, in EP operation, the signal from the brake pipe  14  is high providing appropriate high signal to charge the volume  70  and to bias the pilot three-way valve  62  to the second position connecting the brake signal pipe  33  to the empty load relay valve  26 . Thus the brake apply and release signals on the brake signal pipe  33  from the EP car are provided and a corresponding brake signal on the P car is produced. Volume  70  and choke  68  offers a time delay from a decrease of the signal from the double check valve  66  so as to maintain the three-way valve  62  in the second position when brake pipe pressure goes to zero. This allows the brake signal pipe time to increase its pressure to main valve  62  open to the brake signal pipe. 
         [0022]    On a break-in-two or disconnect, the brake pipe  14  will go to zero or an emergency condition as well as the other brake signal pipe  33  input to the double check valve  66 . Upon the draining of the volume  70  through the choke  68 , the valve  62  will move from its position connecting the brake signal pipe  33  to the empty load relay valve  26  to the position shown in  FIG. 2 . This closes the connection of the brake signal pipe  33  from port  8  of empty load relay valve  26  and connects the brake signal port  3  of the pipe bracket  30  to port  8  of the empty load relay valve  26 . Thus, the standard pneumatic brake valve  10 ,  20 ,  30  applies an emergency brake to the brake cylinders  24 . 
         [0023]      FIG. 3  illustrates another embodiment of the pneumatic brake control valve  60 . The pneumatic valve is shown including pipe bracket  30 , service portion  10 , and a blanking plate  56  instead of the emergency portion  20 . The blanking plate  56  includes a passage  58  connecting the brake cylinder ports at the emergency interface of the pipe bracket  30 . The blanking plate  56  may be used also in  FIG. 2 . In this embodiment, the three-way valve or select valve  62  is replaced by a simple double check valve  72 . The two inputs to the select valve  72  are the brake signal from port  3  of the pipe bracket  30  and the brake signal on the brake signal pipe  33 . Under normal operations, the brake pipe  14  is charged and the pneumatic brake valve  10 ,  20 ,  30  does not provide any signal to the select valve  72 . Thus, the input to the empty load relay valve  26  is the braking signal on brake signal pipe  33 . For an emergency condition, the brake pipe  14  has an emergency pressure which in this case would be zero due to a break-in-two and the pneumatic brake valve  10 ,  20 ,  30  will produce an emergency braking pressure on port  3 . This will force the select valve  72  to provide the emergency braking pressure to the empty load relay  26 . Break-in-two would occur to bring the brake pipe  14  as well as the brake signal pipe  33  to zero. The movement of the select valve  72  will also block off the connection to the brake signal pipe  33 . A volume  64  is connected to port  3  of the pipe bracket  30  to provide proper brake cylinder pressure development during an emergency brake application. 
         [0024]      FIG. 4  shows a further embodiment of the pneumatic brake control valve  60 . The pneumatic brake valve includes a pipe bracket  30 , a vent valve  54 , and a relay valve and charging check valve  76 . The charging check connects the brake pipe port  1  to ports  2  and S to charge the reservoir  22 . The relay valve portion of  76  is responsive to the input on port  10  to provide the braking signal on port  3  directly to the brake cylinder  24 . An empty load device may be provided in between if desired. 
         [0025]    The port  10  of the pipe bracket  30  is connected to a select or double check valve  74 . One of the inputs is from the brake signal pipe  33 . The other input is from the two-positioned piloted valve  78  which is shown spring-biased connecting the reservoir  22  to the select valve  74 . This is the emergency position as long as the brake signal pipe  33  is vented to zero. Piloted valve  78  is piloted to its second position which connects the select valve  74  to atmosphere. A double check valve  66  has an input from the brake pipe  14  on one side and from the brake signal pipe  33  on the other side. The output is provided through choke  68  and volume  70  to produce the pilot signal for the three-way valve or piloted valve  78 . 
         [0026]    Under normal conditions, the brake pipe pressure  14  is high and the double check valve  66  provides the brake pipe pressure to piloted valve  78  to its exhaust position. This allows the transmission of the brake signal from the brake signal pipe  33  to port  10  of the pipe bracket  30 . Thus the relay valve  76  will provide proportional signals to the brake cylinder  24  to that received from the brake signal pipe  33 . In a break-in-two condition, the brake pipe  14  will go low as will the brake signal pipe  33 . Thus, the volume  70  will drain through choke  68  and an appropriate pressure will allow the piloted valve  78  to rise to its shown position connecting the reservoir  22  to the double check valve  74 . This will provide a high signal to port  10  for the relay valve  76  to apply an emergency brake to brake cylinder  24 . This will also seal or disconnect the brake signal pipe  33  from port  10  of the pipe bracket  30 . 
         [0027]    Another embodiment of the brake pipe control valve  60  is illustrated in  FIG. 5 . The pneumatic brake control valve  60  includes a pipe bracket  30  and a vent valve  54 . The other face of the pipe bracket  30  is closed by blanking plate  80 . Brake pipe  14  is connected to the pipe bracket  30  by cut-off cock  12 . The charging of the reservoir  22  from the brake pipe  14  is provided by charging check valve  82  and the choke  84 . These functions were provided in the relay valve and charging check valve  76  in the embodiment of  FIG. 4 . As in the previous embodiment, a piloted three-way valve  78  provides braking pressure from the reservoir  22  for break-in-two condition through double check valve  74 . The other input to the double check valve  74  is the brake signal on the brake signal pipe  33 . Different from the previous embodiment, the output of the select or double check valve  74  is provided directly to the brake cylinder  24  instead of through a relay valve  76  connected to the pipe bracket  30 . As discussed in the previous embodiment, an empty load valve may be provided at the output of the double check valve  74  and connected to the brake cylinder  24 . The piloted valve  78  is piloted by the volume  70  which is charged or discharged by a choke  68  and the double check valve  66 . The input to the double check valve  66  as in the previous embodiment is the brake pipe  14  and the brake signal pipe  33 . 
         [0028]    As in the previous embodiment, under normal operation, when the brake pipe pressure is normally high, the double check valve  66  maintains the volume  70  charged. This pilots the piloted valve  78  to its lower position which disconnects the reservoir  22  from the select valve  74 . This allows the brake signal pipe  33  to control the brake cylinder  24  directly. Under brake-in-two conditions, the output of the double check valve  66  will be at atmosphere on both sides, causing the volume  70  to drain through the choke  68 . At an appropriate low level of the volume  70 , the piloted valve  78  will rise to the shown position connecting the reservoir  22  to the double check valve  74 . This provides an emergency application of the brake cylinder  24  and also closes the connection of the brake signal pipe  33  from the brake cylinder  24 . 
         [0029]    The embodiment of  FIG. 5  also shows a modification of the disconnect valve  31  of the previous figures. The two-way valve  31  is replaced by a relay and charging check valve  90 . The relay and charging check valve  90  is connected to the brake pipe  14  and charges a reservoir  92  through the charging check valve portion. An input signal to the relay valve  90  is the brake signal for the brake cylinder  24  on the EP car. The output of relay valve  90  is connected to the brake signal pipe  33 . The output on brake signal pipe  33  is a proportional signal from reservoir  92  based on the input to the brake cylinder  24 . The relay valve  90  inherently isolates the brake cylinder  24  of the EP car from the brake signal pipe  33 . 
         [0030]    Although the present method has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. As previously mentioned, even though  FIGS. 1 through 3  show a standalone electro-pneumatic brake in the EP car and  FIGS. 4 and 5  show an overlay electro-pneumatic brake in the EP, either style or type of EP brake valve may be used in  FIGS. 1  though  5 . The scope of the present method is to be limited only by the terms of the appended claims.