The Blue Line connects Dwarka to Noida/Vaishali.
The snag led to bunching of trains, the official said.
"The view and control of the signalling and Automatic Train Control system on Blue Line (Dwarka Sec-21 to Noida City Centre/Vaishali) at Operations Control Centre (OCC) were intermittently getting lost today between Karol Bagh and Dwarka section," the official said.
"Between 3:00 to 3:30 pm, the loss of view was for the entire Blue Line, which created bunching on the overall line, before being restored again at 3:30 pm. The intermittent issue was resolved at 4:23 pm and since then train services are running normally on entire Blue Line," he said.
(With inputs from agencies.)