Method and apparatus for sounding horn on a train

Abstract

A method and apparatus for actuating a train horn use the speed of the train to determine when to start a horn sequence such that the horn sequence complies with all applicable regulations. In one embodiment, an engineer enters a command, such as by pushing a button, when a predetermined distance from a grade crossing is reached. A processor then determines the speed of the train from a tachometer. The speed is used to determine how long it will take to reach the grade crossing. Preferably, this calculation is repeated until the time to reach the grade crossing is within a window during which the horn sequence must be started. The processor or other device then causes the horn to sound in the required pattern.

1 . A computerized method for activating a horn on a train comprising the steps of:
 receiving an indication that the train is at a first position, the first position being a known distance from a location at which the horn must be sounded;   obtaining a speed of the train;   determining a time in which the train will reach the location based at least in part on the speed of the train; and   sounding the horn in a predefined pattern if the time is less than a threshold.   
     
     
         2 . The method of  claim 1 , further comprising the steps of repeating the obtaining and determining steps a number of times until the time determined in the determining step is less than the threshold. 
     
     
         3 . The method of  claim 1 , further comprising the step of sounding the horn in the predefined pattern if the speed of the train is above a threshold speed when the indication is received. 
     
     
         4 . The method of  claim 1 , wherein the known distance is 1,320 feet. 
     
     
         5 . The method of  claim 1 , wherein the location at which the horn must be sounded is a grade crossing. 
     
     
         6 . The method of  claim 1 , wherein the speed of the train is obtained from a tachometer onboard the train. 
     
     
         7 . The method of  claim 1 , wherein the indication is received via a switch that is configured to be activated by a train operator. 
     
     
         8 . The method of  claim 1 , wherein the indication is received from an operator of the train. 
     
     
         9 . A device for activating a horn on a train comprising:
 a logic unit;   a first port connected to the logic unit and configured to receive a signal indicative of a speed of the train;   a second port connected to the logic unit and configured to receive a signal indicating that the train is at a first position, the first position being a known distance from a location at which the horn must be sounded; and   an output port connected to the logic unit and configured to output a signal for activating the horn;   wherein the logic unit is configured to perform the steps of
 receiving a signal via the second port indicating that the train is at the first position; 
 obtaining a speed of the train; 
 determining a time in which the train will reach the location based at least in part on the speed of the train; and 
 outputting a signal via the output port such that the horn will sound in a predefined pattern if the time at which the train will reach the location is less than a threshold. 
   
     
     
         10 . The device of  claim 9 , wherein the logic unit is further configured to perform the steps of repeating the obtaining and determining steps until the time determined in the determining step is less than the threshold. 
     
     
         11 . The device of  claim 9 , wherein the logic unit is further configured to perform the steps of comparing the speed of the train to a speed threshold when the train is at the first position and outputting a signal via the output port based on a result of the comparing step. 
     
     
         12 . The device of  claim 9 , wherein the known distance is 1,320 feet. 
     
     
         13 . The device of  claim 9 , wherein the location at which the horn must be sounded is a grade crossing. 
     
     
         14 . The device of  claim 9 , wherein the first port is configured to receive a speed of the train from a tachometer onboard the train. 
     
     
         15 . The device of  claim 9 , wherein the second port is connectable to a switch that is configured to be activated by a train operator. 
     
     
         16 . The device of  claim 9 , wherein the output port is connected to a horn sequencer, the horn sequencer being configured to input a start signal from the output port and, in response to the start signal, output a driver signal that will cause the horn to sound in the predefined pattern. 
     
     
         17 . The device of  claim 9 , wherein the output port is connected to the horn and wherein the signal output by the output port has a time varying pattern corresponding to the predefined pattern.