A locomotive propulsion system onboard a locomotive platform includes a traction motor, a propulsion electrical storage device, an ancillary electrical storage device, and a controller. The propulsion electrical storage device is electrically connected to the traction motor via a propulsion circuit, and the ancillary electrical storage device is electrically connected to the traction motor via an ancillary circuit. The controller is configured to direct the ancillary electrical storage device to supply electric current to the traction motor via the ancillary circuit to power the traction motor during an elevated demand period. At an end of the elevated demand period, the controller is configured to control the ancillary circuit to stop conducting electric current from the ancillary electrical storage device and to direct the propulsion electrical storage device to supply electric current to the traction motor via the propulsion circuit to power the traction motor.