delhi metro is a world-class metro. to ensure reliability and safety in train operations, it is equipped with the most modern communication and train control system. it has state-of-art air-conditioned coaches. ticketing and passenger control are through automatic fare collection system, which is introduced in the country for the first time. travelling in delhi metro is a pleasure with trains ultimately available at three minutes frequency. entries and exits to metro stations are controlled by flap-doors operated by 'smart-cards' and contact less tokens.