hard-wired or radio-controlled—and integrated electronics for locomotive control and operator's cab display systems, DP can now be provided via the ECP brake communication media, and other manufacturers are able to provide this capability. A recent DP system from Wabtec, called PowerLink (which can be either wired or wireless) is in use in Queensland on narrow-gauge coal trains and in the North of Western Australia on standard-gauge iron ore trains. Distributed power in a wired configuration (using the ECP trainline) is becoming increasingly common in North American and Australian heavy-haul unit-train operations. Other similar operations Top and tail is a phrase used to describe an operation where there is a locomotive at each end of the train, usually to make it easier to change direction at a terminal location where it is not possible to run the motive power around the train (i.e. swap the locomotives from one end of the train to the other); this arrangement is not used specifically to operate longer or heavier trains. Top-and-tail operation is not generally utilised with distributed power, although such a configuration could be used as such. One use of a distributed power top-and-tail configuration is in Western Australia's wheatbelt, in which Locotrol provides an operational solution rather than increasing the train size. The description should not be confused with push-pull, which refers specifically to a train configuration (usually associated with passenger trains) in which the motive power is located at one end of the train only. In this latter configuration, the train can be operated from the non-powered end by an operator's control position (the "cab-car") at that end of the train. Distributed traction In a distributed traction system there are no locomotives but power is distributed along the train by multiple traction motors. An electric multiple unit is an example of this system. See also Locotrol Remote control locomotive References External links RailWA: Locotrol Workings – Images of Locotrol operations in the south of Western Australia Locomotives Radio control Rail freight transport