Abstract: A trolley assist-capable electric drive truck includes a DC link with first, second and third contactors that may be opened and closed in different configurations to operate the truck in different modes. In a normal propel mode, the three contactors are open and electrical power is routed from an onboard electrical power source to electric propulsion motors. During normal retard mode, the three contactors are closed to route electrical energy generated by the electric propulsion motors through a grid resistor of the DC link. In a trolley mode, the first and second contactors are closed, but the third contactor is open, and electrical power is routed from the trolley lines to the motors for propulsion, or in a reverse direction for retarding the truck.

Abstract: A system for computing car switching solutions in a railway switch yard. The system is computer based and has an input for receiving data conveying information about one or more arrival trains arriving at the switch yard and data conveying information about departure trains to depart the switch yard. A processing entity processes the data and computes car switching solutions for the railcars.

Abstract: A motor control apparatus for a reversible motor of a railway switch machine includes a conditional power source having an output voltage. A motor control circuit includes inputs for inputting the voltage from the power source, inputs for inputting a normal signal and a reverse signal, two output terminals for electrical connection to two input terminals of the reversible motor, and a relay logic circuit including a pair of double pole, double throw relays. The contacts of these relays: (a) output the voltage to the two output terminals in response to the normal signal, (b) output an inverted polarity of the voltage to the two output terminals in response to the reverse signal, and (c) short the two output terminals in response to absence of both of the normal and reverse signals.