Abstract: A transportation system and method of operation are disclosed wherein a network of nodes, such as railway stations, are defined between which relays, such as freight trains, are operated at a selected cue frequency to thereby provide regular and predetermined service to each node within the system. The system also includes a procedure for interchanging blocks, such as freight cars, which comprise the relays upon arrival at and for departure at the respective nodes. Scheduling of operating crews for return to their respective node of origin during a normal shift period is also disclosed.

Abstract: A system is provided to permit the independent, simultaneous operation of several model railroad train sets along a single track at variable speeds and in the forward and reverse direction, as desired. The system employs apparatus for generating a repetitive ultimate duty cycle and for dividing the duty cycle into spaced apart timewise time slots. During each time slot a train driving voltage of preselected polarity and amplitude is applied to the track. Time gaps are provided between the time slots and during each such gap a control signal of predetermined frequency is applied to the track. The system further includes a sensor mounted in each train and connected to the dc motor of the train. Each sensor is tuned to one of the predetermined frequencies and includes a latching circuit responsive to its frequency which latches the dc motor to the track during the immediately following time slot. The duty cycle and time slots are chosen to permit the trains to operate smoothly and without interruption.