A sorting system includes a train of carriages moving along a track. Each carriage has an electrically driven cross belt for onloading and unloading items to be sorted. Some, but less than all, of the carriages, i.e., master carriages, carry electricity generating equipment, such as a track-engaging wheel connected to an electrical alternator, for converting kinetic energy of the train into electric energy. That energy is made available to all of the carriages through wiring that interconnects the carriages.