The Bush administration said Friday that if a nationwide rail strike looks imminent next week, it will ask Congress for emergency legislation to head it off.

"There is no good reason for a crippling nationwide rail disruption, and this administration is committed to avoiding it," said Transportation Secretary Samuel K. Skinner.Rail unions representing most of the nation's 235,000 freight line workers have vowed to strike at 12:01 a.m. Wednesday, if a 3-year-old dispute over wages and health care isn't settled with the carriers.