The Department of Transportation proposed new rules intended to make transporting flammable materials and crude by rail safer.
The department wants to increase tank car standards and introduce a classification and testing program for mined gases and liquids.
The rules would also add operational requirements for high-hazard flammable trains including braking controls and speed restrictions.
The department said within two years it wants to phase out older DOT 111 tank cars for shipping group I flammable liquids, including most Bakken crude, unless the cars are retrofitted to comply with the new standards.
The department is asking for industry feedback on the proposed rules.
In 2013, about 415,000 rail-carloads of crude were transported in the U.S.