Continuing to tighten airline security following last month's terrorist attacks, the Federal Aviation Administration is limiting passengers to one carry-on bag and a pocketbook or briefcase. All other luggage must be checked.

The FAA restrictions on carry-on baggage mirror the rules imposed on flights to and from Reagan National Airport when it reopened last week.

The federal agency also is telling passengers that they must be prepared to show a photo ID along with their boarding pass at the gate before they board the plane, another step first taken at National Airport. In addition, the carry-on bags may be searched again at the gate.

Airline security remains at its highest level since the Sept. 11 terrorist attacks, and the FAA on Monday again warned airports about security concerns following Sunday's attacks by U.S. and British forces on Afghanistan.

The FAA did not ban curbside check-in, as it did during the Persian Gulf War. Some airlines and airports can offer the service if special security procedures are in place.

The restrictions on carry-on luggage were recommended last week by a Transportation Department task force investigating ways to improve security.

Electronic devices brought aboard planes, such as laptops and cell phones, may be subject to additional screening, the FAA said.

The FAA also issued a list of items that passengers may not carry on board a plane: Knives; any other cutting instruments such as straight razors, box cutters, metal scissors, ice picks and metal nail files; corkscrews; baseball and softball bats; golf clubs; pool cues; ski poles; and hockey sticks.

Passengers may pack safety razors, tweezers, eyelash curlers and nail clippers in their carry-on luggage. They can bring umbrellas and walking canes on board, after they are inspected. Syringes also will be allowed with proof of medical need.

Other tips for travelers include:

--Take public transportation if possible to airports. Parking and the ability to drop passengers off at curbside will be limited.

--For the most part, only ticketed passengers will be allowed past security checkpoints.

--Have all bags and personal items in their control, and they should not bring anything on board for another person.

--Passengers who book their flights online should make sure they get proper documentation from their airline so they can go through security without checking in at the ticket counter.

--Limit the amount of metal they carry with them, and remove all metal objects before going through the X-ray machines at security checkpoints.

The nation's freight railroads, meanwhile, restricted movement of some cargo and activated a full-time crisis center following the military strikes in Afghanistan, the industry's trade group said Monday.

As the attacks began Sunday, railroads began restricting operations near stadiums and other public places where crowds congregated, said Peggy Wilhide, spokeswoman for the Association of American Railroads.

At the request of law enforcement, the railroads have been conducting computer checks of employees against a list of names supplied by the FBI.

Wilhide would not specify which materials were restricted.

Attorney General John Ashcroft on Monday said authorities were not trying to stop all shipments of materials that could be terrorist targets.

"We're asking companies to develop security plans which are reasonable and which provide a way to secure cargo and facilities, but not to cease operations," he said.