Dec. 23: Passengers try to stay warm as they wait for their trains at Union Station in Chicago.
Dec. 22, 2008: Travelers delayed at Terminal 1 at San Francisco International Airport.
Dec. 21, 2008: Hundreds wait for hours to return to the Alaska Airlines counter to get a new booking after their flights were canceled in Seattle.
Dec. 20, 2008: A giant star on a Macy's store shines as heavy snow falls late at night in downtown Seattle.
Dec. 19, 2008: Snow collects on the branches of the Christmas tree in front of the New York Stock Exchange.
Dec. 19, 2008: This NOAA satellite image taken at 12:45 a.m. EST shows cloud cover in the Midwest, where some heavy snow is falling.
Dec. 17, 2008: People play in the snow in front of the Las Vegas welcome sign.
Dec. 14, 2008: Rory Strange of Duluth, Minn., takes a break while snow plowing.
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," 73-year-old Don Seifert said Tuesday 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.
Around 600 passengers in Chicago waited for up to 22 hours before finally boarding their delayed trains — the Lake Shore Limited, which was bound for New York, and the Seattle- and Portland, Ore.-bound Empire Builder.
Amtrak says several trains scheduled to leave Chicago on Tuesday 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 was heading to Rochester, N.Y., to visit family and complained that 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," the 68-year-old said.
Barbara Gruenbacher of Manhattan, Kan., said she, her husband and four kids shivered through the night despite wrapping themselves in blankets as they slept in the station.
"The lack of heat is what put people over the edge," said Gruenbacher, who was also heading to New York to visit family.
Magliari said Amtrak wanted to hear from any disgruntled passengers.
"We want to document what occurred here to develop a better response next time," he said.
Meanwhile, freezing rain was making driving hazardous across parts of the nation's midsection. At least eight people died in car crashes on rain and ice-slickened roads in Missouri, Kentucky, Ohio and Indiana on Tuesday.
The Chicago Department of Aviation said more than 500 flights were canceled at O'Hare International Airport because of the weather, and many others were delayed by up to 2 hours.
Seattle-Tacoma International Airport, the Pacific Northwest's largest, 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 Tuesday was down to "a hundred, if that," said Perry Cooper, an airport spokesman.
Greyhound buses began leaving Seattle at midday Tuesday after service was halted over the weekend, stranding some passengers at the station and at homeless shelters.
Los Angeles International Airport reported scattered delays Tuesday morning, including several flights to Seattle that were delayed.