The MTA will begin a six-year project next month to install modern train signals on a busy stretch of the A and C lines in Brooklyn and Queens, the transit agency announced Thursday.

The $1.9 billion effort aims to install communications-based train control — or CBTC — technology that will allow subway trains to operate automatically at faster speeds along both lines between Lefferts Boulevard station in Ozone Park, Queens, and High Street in Brooklyn.

The signals used by train operators and dispatchers to direct trains on the A and C trains date back to the 1930s. The MTA workers who manage those systems often have no way to know a train's exact position .

“We are saying goodbye to those 1930s signals,” MTA Chair Janno Lieber said at a news conference Thursday. “It's time to turn over those relics to the transit museum and actually install CBTC.”

The modern signal system is used on the L and 7 trains and parts of the E, F, M and R lines. The lines where the MTA has added the new signals are among the most reliable in the city.

Trains on the L and the 7 lines are both driven by computer systems from end to end, but the MTA is still required to station an operator at the front of those trains due to its contract with Transport Workers Union Local 100. Some transit advocacy groups have called for the agency to remove the human operators from automated subway lines as a cost-saving measure.

MTA officials said the upgrades to the stretch of the A and C lines, which operates along four tracks, is the agency’s most ambitious signal upgrade ever. The A line is the longest in the system and serves about 750,000 New Yorkers on an average weekday.

The project isn’t expected to wrap up until 2032, and is set to disrupt riders' commutes in the meantime.

MTA officials said work will begin on the upgrades Nov. 7, a few days after the upcoming elections. The agency will shut down A trains between Rockaway Boulevard and Ozone Park-Lefferts Boulevard for work scheduled to last nine days.

The service outage will affect three stations, and commuters will be given replacement shuttle bus service.

The MTA is behind schedule on several of its other signal upgrade projects.

A report published in 2025 by an MTA consultant found that four ongoing signal modernization projects are facing extensive delays ranging from nine months to three years — and two of those projects were over budget. Those projects aim to add new signals to the A, C and E lines in Manhattan; the F line in South Brooklyn; another stretch of the F line in Eastern Queens; and the G line between Brooklyn and Queens.

MTA construction chief Jamie Torres-Springer said the MTA's next signal “megaproject” will bring the modern technology to the B, D, F and M lines beneath Sixth Avenue in Manhattan.