NEWARK, N.J. (AP) — Several PATH rail stations will close on weekends during the next four months to accommodate work on installing a federally required emergency braking system.

The Port Authority of New York and New Jersey said its World Trade Center and Exchange Place stations will close this weekend for crews to test signals.

Starting the following weekend and continuing through the end of October, stations in Manhattan between Christopher Street and 33rd Street will be closed, though they will be open Labor Day weekend.

The stations will be closed from midnight Friday until 5 a.m. Monday.

The Port Authority said diverted PATH riders in Manhattan will be able to get free, two-trip MetroCards at the 33rd Street station that can be used on city buses and subways.

The Hoboken PATH station will be closed on three Sundays, Sept. 16 and 23 and Oct. 14, but will remain open on the rest of the affected weekends.

All U.S. railroads are required to install the braking system, known as positive train control, on their tracks, towers and rolling stock by the end of December, although some railroads may qualify for two-year extensions.

Port Authority officials said last week PATH is on schedule to meet the Dec. 31 deadline, one of the few railroads in the Northeast likely to do so.

Last week, federal regulators granted New Jersey Transit's request for a two-year extension to install the system.