Rail officials across Europe and the United States are tightening security following the deadly bombings in Madrid.

France deployed hundreds of troops at transportation hubs, especially high-speed rail lines. British officials warn their country's rail system could be a target for the al-Qaida terror network. Italian officials are reviewing the nation's anti-terrorism measures, but say the Madrid bombings are not prompting exceptional new measures.

European transportation officials are reluctant to institute the kind of security measures familiar to airline travelers -- metal detectors, baggage searches, and passenger screening. They say such measures would make the railroads slower and more expensive.

Rail authorities in the United States are also bolstering security, especially in the crowded northeastern part of the country.

Officials have put more security teams, bomb-sniffing dogs, and electronic surveillance equipment in Washington and New York City, as well as western U.S. cities of Seattle, Washington and San Diego, California.

Security experts say rail transport security has lagged far behind commercial aviation. U.S. lawmakers are considering a proposal to provide an additional half-a-billion dollars to close the gap.