A fail-safe or fail-secure describes a device which, if (or when) it fail, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel. Examples include: · Luggage carts in airports in which the hand-brake must be held down at all times. If it is released, the cart will stop. See dead man's switch. · Air brakes on railway trains and trucks. The brakes are held in the 'off' position by air pressure created in the brake system. Should a brake line split, or a carriage become de-coupled, the air pressure will be lost and the brakes applied. It is impossible for the train to be driven with a leak in the brake system. · Avionics using redundant systems to perform the same computation with voting logic to determine the "safe" result. · Motorized gates - In case of power outage the gate can be pushed open by hand with no crank or key required. However, as this would a