CHICAGO - On one of the biggest travel days of the year, hundreds of Amtrak passengers bound for holiday destinations hunkered down in waiting rooms - some for nearly 24 hours - as snowstorms and Arctic cold delayed their trains and disrupted other Christmas traffic.

Don and Barbara Seifert of Prophetstown, Ill., spent a sleepless, frustration-filled night at Chicago's Union Station with hundreds of angry customers.

After waiting 12 hours for their New York-bound train to depart, their breath visible in the frigid indoor air, the Seiferts finally abandoned plans to visit their son and his family for the holidays.

"It's spoiled our Christmas, sure," Don Seifert, 73, said yesterday before he and his wife headed back to their western Illinois home.

Amtrak spokesman Marc Magliari said crews in some cities headed out with picks and shovels to clear snow-packed track switches; elsewhere, trains were held back to give lavatory pipes time to thaw.

Each train delay caused a ripple effect, with other trains and their crews at other points having to wait or readjust, he added.

"A combination of all those things is what presented this situation, about which we're very regretful," Magliari said.

About 600 passengers in Chicago waited for up to 22 hours before finally boarding their delayed trains - the Lake Shore Limited, bound for New York, and the Empire Builder, headed to Seattle and Portland, Ore.

Amtrak said several trains scheduled to leave Chicago yesterday were canceled. Passengers on shorter-distance trains were put on buses instead.

Many passengers weren't happy with how Amtrak dealt with the delays. Sydney Cochran, 68, was heading to Rochester, N.Y., to visit family and said Amtrak didn't offer blankets, pillows or food overnight. She added that no one provided clear answers about when the train might leave, if at all.

"I'm furious," she said.

Magliari said Amtrak wanted to hear from any disgruntled passengers.

Meanwhile, freezing rain was making driving hazardous across parts of the nation's midsection. At least eight people died in car crashes yesterday on rain- and ice-slickened roads in Missouri, Kentucky, Ohio and Indiana.

More than 500 flights were canceled at Chicago's O'Hare International Airport because of the weather, and many others were delayed up to two hours, the Chicago Department of Aviation said.

Seattle-Tacoma International Airport had been jammed with thousands of stranded travelers Sunday night and Monday morning. But most air service was restored Monday, and the number of people sleeping in the terminal early yesterday was down to "a hundred, if that," said airport spokesman Perry Cooper.

Greyhound buses began leaving Seattle at midday yesterday after service was halted over the weekend.