WASHINGTON — Amtrak has rolled out wireless Internet access on all 20 of its Acela Express trains between Washington and Boston and in six major stations along the northeast corridor.

The service is free for now, though the railroad says that policy will be reviewed after an introductory period.

Wireless is now available inside the gate areas of Washington Union Station, Baltimore Penn Station, Philadelphia 30th Street Station, New York Penn Station, Providence Station and Route 128 Station in Boston, as well as on board the Acela. Amtrak says Wilmington Station will be Wi-Fi equipped once station renovations are completed in 2011.