A 300-foot stretch of an elevated railroad trestle caught fire Thursday evening, sending a dramatic wall of thick, black smoke thousands of feet into the air and disrupting rail traffic through the state capital.
The blaze forced Amtrak to halt a westbound train from Reno to Sacramento, said George Elsmore, railroad operations and safety program manager for the California Public Utilities Commission.
He said the fire also was likely to disrupt freight traffic throughout Northern California.
"This is a main line for the Union Pacific. It's a major line right over the American River," he said.
Fire officials said they had not determined how the blaze started. But the creosote-soaked trestle -- which keeps trains elevated above local roads and a wetlands area -- fueled an intense fire that could be seen from more than 50 miles away.
The spectacle drew a crowd of hundreds of pedestrians from nearby hotels and stores and crippled rush-hour traffic on the Capital City Freeway around Cal Expo, the state fairgrounds. The fire also had cut power to some local stores.
The trestle, which was buckling and appeared ready to collapse, supports a key rail artery leading into Sacramento.
Officials reported that several Amtrak trains were scheduled to travel through that section of track and were being stopped. Freight lines also are expected to be stalled by the fire, Union Pacific spokesman James Barnes told The Sacramento Bee.
"It certainly is one of our main lines," Barnes said. "We are anticipating that the trestle will not survive. The important thing now is get that fire under control and out, and then we can better assess the situation."
No train was involved in the fire, he said.
Emergency workers used loudspeakers to tell pedestrians to stay out of the path of the smoke, fearing it may be hazardous. The wall of smoke extended an estimated 2,000 feet into the air and bent in a giant S-curve, blanketing the capital skyline.
Christian Pebbles, a Sacramento Fire Department spokesman, told KCRA-TV that the relatively remote location of the fire was making it difficult for firefighters. There were no water hydrants nearby.
Firefighters, however, were using what water they could get to the site to make a defensive stand near a levee on the American River, Pebbles said.