Distributed power

In rail transport, distributed power (DP) is a generic term referring to the physical distribution—at intermediate points throughout the length of a train—of separate motive power groups. Such 'groups' may be single units or multiple consists, and are remotely controlled from the leading locomotive. The practice allows locomotives to be placed anywhere within the length of a train when standard multiple-unit (MU) operation is impossible or impractical. DP can be achieved by wireless (RF connectivity) or wired (trainlined) means. Wired systems now provided by various suppliers use the cabling already extant throughout an ECP train. In rail transport, distributed power (DP) is a generic term referring to the physical distribution—at intermediate points throughout the length of a train—of separate motive power groups. Such 'groups' may be single units or multiple consists, and are remotely controlled from the leading locomotive. The practice allows locomotives to be placed anywhere within the length of a train when standard multiple-unit (MU) operation is impossible or impractical. DP can be achieved by wireless (RF connectivity) or wired (trainlined) means. Wired systems now provided by various suppliers use the cabling already extant throughout an ECP train. The greatest benefit of Distributed Power—and the reason for development of the original concept—is the reduction of drawgear draft forces, permitting a wholesale increase in the size of trains without exceeding draw-gear strength, through the use of mid- or end-of-train locomotives. There are also potential train-handling benefits. Over an undulating track profile, a skillful operator can manipulate the relative power outputs (as well as dynamic- and air-brake applications) to minimize run-in and run-out of coupler slack throughout the train.'