A rocket-powered sled shot down a 3-mile straightaway in about six seconds to break a world record that had stood for two decades.

The monorail sled set the land speed mark for rail vehicles early Wednesday at the Holloman High Speed Test Track, testing a 192-pound bullet-shaped payload being developed by the 846th Test Squadron and the Missile Defense Agency.

The test, in a remote area of the base, started with a brilliant, multihued blaze of rocket engines and ended in a spray of sparks when a missile carried by the sled slammed into an immobile target. There was silence until a split second before the end, when earsplitting bursts rolled across the desert floor.

"Psychologically, you think it's over. But then comes the sonic boom. I know it's coming. But I always jump a little," said Lt. Col. Russ Kurtz, director of operations.

Preliminary numbers put the sled's speed at Mach 8.6 -- almost nine times the speed of sound -- or about 6,400 mph, said Lt. Col. James Jolliffe, 846th Test Squadron commander. The previous record was Mach 8, or 6,122 mph, set on Oct. 5, 1982, also at Holloman.

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