As oil production in the Bakken area of North Dakota and Montana skyrockets, rail companies are capitalizing on pipeline gaps and reaping profits by transporting the crude while environmental watchdogs call the practice "an accident waiting to happen."

Reuters reports that "it's a booming business for North America's railroads, and should remain an important niche market for years to come."

“BNSF has been hauling Bakken crude out of the Williston Basin area for over five years. In that time, we have seen the volume increase nearly 7,000 percent, from 1.3 million barrels in 2008 to 88.9 million in 2012,” Dave Garin, BNSF group vice president, Industrial Products, stated in September. “We see this trend continuing and we are committed to serving this growing market now and in the future.”

Union Pacific Corp. chief executive Jack Koraleski also sees the continuing oil boom as profit boom for his industry.  "We think we're going to continue to grow the oil business. The rate of growth will slow from its current over-excited pace, but we still think it will continue to be a good business for us," he told Reuters.

And Jeffery Elliot, a rail expert with the New York-based consulting firm Oliver Wyman, told the Associated Press, "The railroads are looking at this as a unique opportunity, a game-changing opportunity for their business."

While rail executives see dollar signs by hauling the oil, critics warn the risk of disaster is high.

"This is all occurring very rapidly, and history teaches that when those things happen, unfortunately, the next thing that is going to occur would be some sort of disaster," Jim Hall, a transportation consultant and former chairman of the National Transportation Safety Board, told AP.

AP adds that the Association of American Railroads even acknowledged that the likelihood of a rail accident could be double or triple that of a pipeline problem.

"It's an accident waiting to happen. It's going to be a mess and we don't know where that mess is going to be," Wayde Schafer, a North Dakota spokesman for the Sierra Club told AP, and described using rails over pipelines as "the greater of two evils."

As environmentalists concerned over spills continue to thwart pipeline progress and advocate for clean energy, the new stage of direct actions may be on the nation's rails.