That potential security risk could also force the national rail service to install gun-safe storage compartments and add security checkpoints, causing long lines on a system with a steadily increasing ridership, Amtrak says.

In a letter to congressional leaders, New Jersey Governor Jon Corzine said he was "outraged" that the U.S. Senate, by a 68-30 vote, agreed last week to permit Amtrak passengers to transport firearms and ammunition in their checked baggage.

Corzine said he will "not allow the NRA to force guns to be transported or carried" into stations that serve New Jersey’s urban centers and major universities, such as Newark and New Brunswick.

"Mandating our national railroad to hold and transport firearms in unsecured baggage areas across America is both deplorable and ludicrous in a post-9/11 world," he said.

Gun-rights advocates said Amtrak’s current policy prohibiting people from transporting any firearm, ammunitions, explosives or similar weapons unfairly penalizes law-abiding passengers.

The National Rifle Association noted that guns are permitted aboard planes as long as the weapon is unloaded and stored safely and separately from the passengers.

"It would be mindful for people that Amtrak is nationwide," said Andrew Arulanandam, an NRA spokesman. "There are people who use it and have a need to carry firearms for a lawful purpose."

The amendment to the transportation and housing appropriations bill still needs President Obama’s signature — a long shot, some say, because of Obama’s past opposition to gun-rights legislation.

A House version of the bill was passed in July, but does not include the amendment.

Rep. Bill Pascrell Jr., D-N.J., believes Amtrak has neither the money nor the personnel to safely protect its 27 million annual riders from gun-toting passengers.

Relaxing firearms restrictions, he said, could also encourage terrorists to transport weapons and pose a security threat.

"Sept. 11 is still with us, and if they (amendment supporters) think the rails have become safer, they’re wrong," Pascrell said.

The measure says Amtrak would lose its federal subsidies if it doesn’t establish a system for protecting passengers from firearms by early next year — a deadline that Amtrak officials aren’t sure they could make.

More than a week after the Senate bill passed, Amtrak spokesman Steve Kulm said the agency is still unsure how to proceed. If the bill becomes law, however, the agency would work with the Transportation Security Administration in establishing a security system, he said.

The TSA declined to comment.