The Association of American Railroads said in its weekly assessment of rail traffic less than half of the commodity groups typically carried by rail posted increases compared with the same week in 2012.
For the first 33 weeks of the year, total rail traffic was up 2 percent from the same time last year. Petroleum and petroleum products increased 19.6 percent when compared with the same week last year, AAR said in a statement Thursday.
BNSF Railway Co. said this week it plans to invest $115 million on rail projects in Montana this year, including the replacement of nearly 100 miles of rail. A $220 million investment in North Dakota finances the replacement of about 315 miles of rail this year.
The U.S. Energy Department said the Bakken oil reserve area under Montana and North Dakota could potentially give up as much as 3.7 billion barrels of oil.
Oil companies in the United States are turning to rail because production increases have outpaced existing pipeline capacity.