A serial copper thief brought the subways to a screeching halt last month when his wire-snipping escapades rendered tunnel traffic lights useless, causing hundreds of delays , the MTA revealed this week.

A scrap metal swindler, identified as 55-year-old Efrain Velez, stopped service on three separate days in October when he snatched copper wires straight off the train tracks at the Bronx 149th Street Grand Concourse station.

A serial copper thief was busted last month for stealing copper wires in a subway tunnel. Christopher Sadowski

Officials revealed the wire-grabbing spree caused the Grand Concourse tunnel traffic lights to switch from green to red — ultimately delaying over 755 subway trains on the 1, 2, 3, 4, 5 and 6 lines.

“The primary driver of October’s weekday on-time per

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