President Bush has signed into law sweeping improvements in railroad safety that might have prevented the deadly collision of a commuter train and a freight train in Los Angeles last month.

Bush signed the legislation Thursday without fanfare. The bill sped through the House and Senate after the Sept. 12 crash that killed 25 people, drawing new attention to safety gaps.

The law will require more rest for workers and technology that can stop a train in its tracks if it's headed for a collision. Federal officials say such technology would have prevented the Los Angeles crash.

The bill also calls for Amtrak to receive $13 billion over five years in subsidies, though Congress will have to separately approve the money year after year.