Patent ID: 7664459
Filing Date: 2010-02-16
Classification: B61L,H04B

Abstract:
1. A communications method for a railroad train comprising a lead locomotive and at least two remote locomotives, the method comprising: transmitting an outbound message from the lead locomotive for receiving by all remote locomotives that are within communications range of the lead locomotive; at each remote locomotive that receives the outbound message, storing the outbound message, and transmitting the outbound message during an outbound time slot defined for the receiving remote locomotive, wherein each remote locomotive transmits the outbound message before transmitting an inbound message; at a remote locomotive configured as the last locomotive, receiving the outbound message, and transmitting an inbound message comprising a response of the last remote locomotive to the outbound message; at each remote locomotive that receives the inbound message, except the last remote locomotive, storing the inbound message, appending a local status message and transmitting a modified inbound message during an inbound time slot defined for the receiving locomotive, wherein the inbound message that reaches the lead locomotive comprises a response to the outbound message from each remote locomotive that received the outbound message; at the lead locomotive, determining whether a reply was received from all remote locomotives, and in the event a reply was not received from one or more of the remote locomotives transmitting the outbound message again; wherein the outbound time slots and the inbound time slots are responsive to a number of remote locomotives in the train and a time slot is assigned to each remote locomotive based on a position of the remote locomotive in the train; and wherein a beginning time of an outbound and an inbound time slot for a remote locomotive is modified if one or more other remote locomotives do not transmit an outbound message or do not transmit an inbound message.