Section 16(1)(e) in The Delhi Metro Airport Express Line, General Rules, 2010
(e)Messages;(ii)if the target speed indication and the target distance indications, where provided, are greater than zero, the indication is referred to as "Proceed" indication;(iii)if either of these indications is "0", the indication is referred to as "Stop" indication;(iv)The train operator is authorised to drive his train up to the indicated speed as far as authority has been given for such purpose.