public void updateTrainComboBox(JComboBox<Train> box,Car car){
  box.removeAllItems();
  box.addItem(null);
  for (  Train train : getTrainsByNameList()) {
    if (train.services(car)) {
      box.addItem(train);
    }
  }
}

public void updateTrainComboBox ( JComboBox < Train > box , Car car ) { box . removeAllItems ( ) ; box . addItem ( null ) ; for ( Train train : getTrainsByNameList ( ) ) { if ( train . services ( car ) ) { box . addItem ( train ) ; } } }
update combo box with trains that will service this car
