April 2014, PN coal waggons.  Distributed power Main article: Distributed power Distributed power is a system where locomotives are coupled in the middle and/or end of a heavy train and remotely controlled originally via radio from the locomotive in the front. Amongst other advantages, this reduces coupling stresses in long and heavy trains. The ECP wiring can also be used to control these intermediate locomotives. Parameters Standard = Association of American Railroads S-4200 Train Length = 3,658 m (12,001 ft) maximum Wagons (Network Devices) = 180 Wired Distributed Power (WDP) = 230 V DC See also Railway air brake New York Air Brake (equipment supplier) Wabtec (equipment supplier) Electronically Controlled Brake.