The MTA has officially begun a major signal modernization project on the G line, with Brooklyn commuters feeling the brunt of the impact this summer.

The $368 million project will replace the line’s aging signal system, some of which dates back to the 1930s, with modern Communications-Based Train Control (CBTC), aimed at making service faster and more reliable.

The full upgrade is expected to be completed by 2027 and will include new open-gangway trains.

Starting this week, there will be no G train service between Court Square and Bedford–Nostrand Avenues on most weeknights and weekends through mid-August.

Riders are already expressing frustration.

“It’s going to affect me a lot. I travel this way every day,” said one commuter. “Now they’re having these track repairs.”

The MTA will operate shuttle buses every few minutes during service changes.

Commuters are urged to check the MTA train time app for the latest real-time updates.