A distributed power train (10) communications system for sending and
receiving signals between a lead locomotive (14) and remote locomotives
(12A/12B/12C) in the train (10). A lead (14) initiated message is
received by at least the remote locomotive (12A/12B) nearest to the lead
unit (14). The receiving remote unit (12A/12B) retransmits the message
for receiving by the next remote unit (12C) in the train. Thus the
message leapfrogs down the train from the lead unit (14) to the remote
units (12A/12B/12C). When the last remote unit (the nth remote unit)
(12C) receives the message, the last remote (12C) transmits a status or
other response message to the lead unit's message. The status message is
received at the (n-1)th remote unit (12A/12B), which appends its status
message and transmits the combined status messages toward the lead unit
(14). Each successive remote unit receives the status messages of the
other remote units and appends its status message, until the concatenated
status message reaches the lead unit (14).