During the day, the guard uses the traditional green flag to signal the pilot to depart, and the red flag to stop, assisted by two-way radios. After sunset, the guard uses lamp signals in place of the flags. A couple of minutes before signalling departure to the pilot, the guard blows a whistle to warn passengers to board the train. After ensuring all passengers are safe to travel, the guard signals the green flag by waving it from the brake van. In an emergency, the guard uses the red flag to indicate a stop, and may directly apply brakes to stop the train. The pilot is not allowed to move the train without a signal from the guard, as the guard is in charge of the train.