WASHINGTON — An energy boom that has created a sharp increase in rail freight traffic nationwide is causing major delays for Amtrak passenger trains and is holding up the transport of vital consumer and industrial goods, including chemicals, coal and hundreds of thousands of new American cars, rail officials and federal and state regulators say.

American rail lines now move more than a million barrels of oil a day, much of it from the Bakken shale oil field in North Dakota and Montana and from the oil sands of Alberta, Canada. Last year about 415,000 rail cars filled with crude oil moved through the United States, compared with 9,500 in 2008, according to the Surface Transportation Board, a bipartisan body with oversight of the nation’s railroads.

In large part as a result, long-distance Amtrak passenger trains are now late 60 percent of the time, Amtrak officials said, compared with a year ago, when the trains were late 35 percent of the time.

The problems are particularly acute on long-distance passenger lines like the Empire Builder, which shares tracks with freight traffic from Chicago to Portland, Ore., and is late nearly 70 percent of the time. Trains on the 47-hour trip typically run three to five hours behind. Revenue from the line has dropped 18 percent from last year, Amtrak officials said, as word about the sluggish service spread among passengers, most of whom use the Empire Builder for shorter trips between cities on the route.