A Delhi Metro Rail Corporation or DMRC official said services slowed down at 8 am on the entire Violet Line between Faridabad and Kashmere Gate after trains lost touch with the control centre.
As the centralised control mechanism snapped, trains had to be manually controlled from every station on this section between 8 am and 9 am, leading to long delay. "The issue was resolved at 9 am and trains are now being regulated as per normal schedule on Line 6," the official said.
Later, a fault in the signalling system on the Blue Line led to delay. Blue Line is Delhi metro's longest and busiest corridor that connects Noida and east Delhi's Vaishali to west Delhi's Dwarka.
Earlier this year, following sudden power failure and resulting loss of contact between trains and the control centre, services were crippled on the Blue Line for two successive days.
Following the incident, an alternative mechanism that handled trains from station to station called "station-level handling" was activated.