may also be used to allow the engineer conductor to acknowledge the warning in some embodiments the warning device 170 is in the form of a button on an operator display such as the display illustrated in co pending u s application ser no 10 186 426 entitled u201c train control system and method of controlling a train or trains u201d filed jul 2 2002 the contents of which are hereby incorporated by reference herein in other embodiments the warning device 170 may be a stand alone button that illuminates when a malfunction is detected in yet other embodiments e g those in which no acknowledgment of a warning is required the warning device 170 may comprise or consist of a horn or other device capable of providing an audible warning 0025 fig2 is a flowchart 200 illustrating operation of the control module 110 in connection with a track circuit 180 in one embodiment of the invention in this embodiment which is particularly well suited for use with track circuits such as broken rail detection circuits and avalanche detection circuits the train will be preferably be brought to a complete halt either by the operator or automatically by the control module 110 if the operator fails to take action before reaching the section of track monitored by the track circuit forcing the train to come to a complete stop forces an operator to make a positive decision to move the train forward through the section of.