The Port Authority of New York and New Jersey will spend $809 million on new and refurbished rail cars for its PATH system linking northern New Jersey with Manhattan.

The bistate agency issued a request for proposals yesterday from contractors interested in repairing or replacing its entire rail fleet. The program would buy 246 new cars and rehabilitate or replace an additional 94 cars.

The spending would be the largest single investment in PATH since the Port Authority acquired it from the Hudson and Manhattan Railroad in 1962.

The first of the new cars should be in service in late 2008 or early 2009, and the entire fleet is to be replaced or rehabilitated by 2011.

"For more than 40 years, the PATH system has provided a key mass transit option that allows commuters to send less time in their cars and more time with their families," Gov. James E. McGreevey said. "These new cars will demonstrate our unwavering commitment to public transportation in New Jersey and will help my administration improve the quality of life for all commuters by reducing congestion at our bridges and tunnels."

The Port Authority is working on plans for a new transportation hub at the World Trade Center site.

The new cars will feature improved lighting, air conditioning and heating systems; cantilevered seats with room for passengers to store items underneath; prerecorded station announcements; better signs, and three doors on each side to permit faster loading and unloading.

The authority hopes to award a contract for the new cars later this year.