Abstract:
A test device includes a trainline connector for connecting the test device to a car trainline to which the electropneumatic brake device is connected and includes a power port to receive power for the trainline at a first voltage. A power switch selectively connects the power port to the trainline connector. A test switch selectively connects a test voltage smaller than the first voltage to the trainline connector. A sensor senses an electrical parameter of the trainline. A controller a) initially controls the power switch to disconnect the power port from the trainline connector, b) subsequently controls the test switch to connect the test voltage to the trainline connector and c) if the sensor senses an electrical parameter indicative of an acceptable trainline, controls the test switch to disconnect the test voltage from the trainline connector and controlling the power switch to connect the power port to the trainline connector.

Description:
BACKGROUND AND SUMMARY OF THE DISCLOSURE 
       [0001]    The present invention relates generally to electrically controlled pneumatic (ECP) brake systems on trains and, more specifically, to a test device for ECP brake device on a car. 
         [0002]    Electrically controlled pneumatic brake systems on trains have a head end controller which is connected to a trainline to transmit power and control signals to electro pneumatic brake devices on each of the cars. The head and trainline controller may include software for testing a signal quality on a trainline network. Such a device is described in U.S. Pat. No. 6,759,971. Signals transmitted down the trainline commands each node to transmit a calibration signal. The signal quality is determined based on the receipt of the calibration signal. 
         [0003]    The method for preventing shock or powering of an electric trainline in an ECP brake system until a test system transmitted through the trainline is verified by the locomotive is described in U.S. Pat. No. 5,673,876. The test signal is at a lower voltage than the power signal that is normally applied to the trainline. Whether there is a safe transmission, is determined by a device at the other end of the trainline. 
         [0004]    A method of setting ECP brakes to modes of operation in small groups of cars is described in U.S. Pat. No. 6,979,061. A wake-up signal-voltage less than the regular train voltage is applied and the communication to the each of the devices on the individual cars is established. 
         [0005]    A single car tester for ECP equipped cars are presently available. These testers do not include testing of the integrity of the trainline within the individual car. The present test device provides a test for the trainline integrity of the individual cars. 
         [0006]    The present test device for an electro pneumatic brake device on a rail car includes a trainline connector for connecting the test device to a car trainline to which the electro pneumatic brake device is connected and includes a power port to receive power for the trainline at a first voltage. A power switch selectively connects the power port to the trainline connector. A test switch selectively connects a test voltage smaller than the first voltage to the trainline connector. A sensor senses an electrical parameter of the trainline. A controller a) initially controls the power switch to disconnect the power port from the trainline connector, b) subsequently controls the test switch to connect the test voltage to the trainline connector and c) if the sensor senses an electrical parameter indicative of an acceptable trainline, controls the test switch to disconnect the test voltage from the trainline connector and controlling the power switch to connect the power port to the trainline connector. 
         [0007]    The trainline includes two conductors and the test switches includes two conductor test switches each selectively connects a respective conductor to one of the test voltage and ground, as controlled by the controller. The test switch includes a ground test switch selectively connecting a ground port to one of the test voltage and ground, as controlled by the controller. The sensor senses the electrical parameter of each conductor and of the ground port. 
         [0008]    The sensor senses current in the trainline. The controller determines an acceptable trainline if the sensed current is indicative of an impedance above a threshold. 
         [0009]    The power switch includes a first and second test switches. The first test switch selectively connects the power port to the second test switch when closed; and the second power switch selectively connects one of the test switch and the first power switch to the trainline connector. The controller opens the first power switch before connecting the test switch to the trainline connector using the second power switch. 
         [0010]    The controller conducts a test of the electropneumatic brake device after controlling the power switch to connect the power port to the trainline connector for an acceptable trainline. For an unacceptable trainline, the controller controls the power switch to connect the power port to the trainline connector after an acknowledgement from the operator. 
         [0011]    These and other aspects of the present disclosure will become apparent from the following detailed description of the disclosure, when considered in conjunction with accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a block diagram of a single car tester for an ECP brake according to the principles of the present disclosure. 
           [0013]      FIG. 2  is a schematic of the trainline integrity portion of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    A test device  10  as illustrated in  FIG. 2  has a power port  14  connected by cable  12  to a source of power. This may be a standard electrical outlet or any other source of power. A trainline connector  16  is connected by cable  17  to the tester  10 . Connector  16  is an approved trainline electrical connector for ECP cars. A ground port  18  is connected by cable  19  to a car ground for example, a car body. 
         [0015]    The power port  14  is connected by an on/off switch  20  to a power regulator  22 . The power regulator provides two out volts V 1  and V 2 . V 1  may be, 15 volt for example, 115 volts which is higher than the 100 volts DC, known as the wake up voltage for ECP systems. This is sufficient voltage to wake up and run tests on the car control device (CCD) on the car. The second voltage V 2  may be for example 15 volts DC. This is sufficient voltage to perform the trainline integrity test. The voltage V 1  is connected by  24  to a power switch  30 . The power switch  30  is controlled by the controller  60  via control  82 . The output  31  of the power switch  30  is connected to the trainline port  17 . The test voltage V 2  is connected by  26  to the test switch  40 . The test switch  40  has an output connected to the car ground port  18 . It receives a control via  84  from the controller  60 . The output  41  of test switch  40  is also connected to the trainline port  17 . A sensor  50  is connected by  51  to the trainline port  17  and senses an electrical parameter of the trainline. It is also connected to the controller  60  by  86 . A push button  662  is connected to the controller  60 . An indicator  64  is connected to the controller  60 . 
         [0016]    Test device  10  includes a standard ECP tester  70  controlled by the controller  60  via  88  and having a connection  71  to the trainline port  17 . Since the ECP tester  70  forms no part of the present invention other than being part of the test device  10  it will not be described in detail. Typical ECP testers may be available from (please list what these testers are and where they are, also verify if the are a part of the controller  60  or they are a separate tester  70 ). 
         [0017]    The single car trainline integrity test is used to detect for example a low impedance path between the two conductors of the trainline power wiring, and to detect a low impedance path between either of the two trainline power conductors and chassis ground. This test is intended to be completed before the newly ECP equipped rail car is connected to a power source. The test is designed to prevent property damage, personal injury, or death, in the event that gross unsafe deficiencies exist in the wiring on the rail car. 
         [0018]    Once the electro-pneumatic braking equipment installation has completed, the test apparatus  10  is connected to the trainline power interface of the rail car by connector  16 . The test apparatus is connected to line voltage by plug  12 , and turned on by switch  20 . But before it applies line voltage V 1  to the brake equipment, the operator initializes the tester  10  by pressing the push button  62 . The circuitry including power switch  30  inhibits the test apparatus from applying line voltage V 1  to the rail car, and drives the indicator  64  to indicate the test has started and line voltage V 1  is inhibited to the rail car, but the results of the test are yet unknown. Using one or more duel element LEDs, both the red and green elements of each of the LED indicators would be activated, such that they glow orange. 
         [0019]    The circuitry tests for low impedance between any of the conductors by applying a test voltage V 2  of for example 15 volts DC supply to one conductor, and ground to another. Power and ground to the conductors are switched by test switch  40 , which may be a solid-state push-pull driver. A series resistance is implemented to detect the current draw through any path that is formed when the drivers are active. If the current draw indicates an impedance of less than 15,000 ohms for example, a fault is indicated by switching the appropriate LED from orange to red. If the current draw indicates an impedance of greater than 15,000 ohms, the test passes and the LED is switched from orange to green. Execution of the test is controlled by the controller  60  containing an embedded software program. 
         [0020]    Troubleshooting when a fault is detected is simplified through the use of the three bicolor LEDs. Each LED is dedicated to representing a low impedance fault condition between any or all of the following: trainline conductor ‘A’ and trainline conductor B′, trainline conductor ‘A’ and chassis ground, and trainline conductor ‘B’ and chassis ground. 
         [0021]    At the completion of all testing, if no faults are detected, all of the LEDs are illuminated green, and remain illuminated for approximately two seconds. At the end of the two second period. the line integrity portion of the tester  10  shuts down, and restores the ability to apply nominal voltage from the test apparatus  10  to the electro-pneumatic braking system. If any faults are detected, they are indicated by one or more LEDs illuminated in red. In this case, the faults remain indicated and the ability of the test apparatus to apply nominal voltage to the electro-pneumatic braking system remains inhibited. This is so the operator must acknowledge the faults before continuing by pressing the normally open push button  62 . After the button press, the LEDs hold their states for two seconds, and then nominal voltage may be applied to the electro-pneumatic braking system by power switch  30 . 
         [0022]    The controller  60 , which coordinates all functions of the tester  10 , contains sufficient EEPROM such that data may be collected for analysis at any time the test apparatus assembly is returned for repair or upgrade. This data includes the total numbers of the following: tests that have been run, tests in which no faults were detected, tests indicating a fault between trainline conductors ‘A’ and ‘B’, tests indicating a fault between trainline conductor ‘A’ and chassis ground, and tests indicating a fault between trainline conductor ‘B’ and chassis ground. 
         [0023]    An example of the circuitry for the power switch  30 , the test switch  40  and the sensor  50  is illustrated in  FIG. 2 . The test voltage V 1  at line  24  is provided to a first power switch PSW 2  which has a switch operator  35  normally closed on contacts  36 . This provides a connection  31  to contacts  33  of a power switch PSW 1 . The operator  32  of PSW 1  is normally closed against contacts  23 . The operator  32  is connected to line A at  17 A and line B at  17 B of the trainline connector  16 . Thus in the normally closed position of the power switch PSW 1  and PSW 2 , the higher voltage V 1  is supplied across line A and line B of the trainline of the car. 
         [0024]    As previously described, upon activation of push button switch  62 , the controller  60  provides the signals to control the power switches PSW 1  and PSW 2  to disconnect the voltage V 1  from the lines A and B and connect the test circuit to lines A and B. Thus PSW 2  is open off its close contacts  36  and operator  32  removes from contacts  33  to contacts  34 . This connects the line A and line B to connections  41 - 51  of the tester switch  40  and the sensor  50 . To reduce arcing, PSW 2  maybe open first to disconnect the voltage V 1  from switches PSW 1  before it changes its connection from contacts  33  to contacts  34 . When the system has returned from the test to applying of the voltage V 1  to the trainline, PSW 1  may be closed back on contacts  33  before the connection PSW 2  to its contacts  36 . 
         [0025]    The test switch  40  includes three test switches  42 ,  44 , and  46  each for selectively controlling of the continuity test voltage V 2  or ground to the respectively lines A, B and ground ports  17 A,  17 B and  18  respectfully. The test switches  42 ,  44 , and  46  are under the control of controller  60  and, as discussed above may, be solid-state push-pull drivers. The output of the test switch  42 ,  44 , and  46  are provided by a line  41  to a voltage divider R 1  and R 2 . The center tab of the voltage divider is provided through fuse F to the appropriate terminals  34  for line A and line B and to  18  for the ground port. The resistors R 1  and R 2  are selected so as to detect a current which indicates an impedance less than or greater 15,000 Ohms. 
         [0026]    The sensor  50  includes three operational amplifiers  58  each connected by line  51 , fuse F to contacts  34  for line A and B and directly to port  18 . 
         [0027]    Controller  60  is illustrated as having appropriate outputs to control the power switches PSW 1  and PSW 2 , the test switches  42 ,  44 , and  46  and receive the sensing inputs from operational amplifiers  58 . Also for indicators  64 . 
         [0028]    Although the powers switches PSW 1  and PSW 2  are illustrated as electromagnetic switches they may solid state switches or any equivalent thereto. 
         [0029]    Although the present disclosure 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. The scope of the present disclosure is to be limited only by the terms of the appended claims.