Oil shipments by rail from the booming Bakken shale in North Dakota have slowed over the past two days, data showed on Friday, but a U.S. regulator knocked down rumors that some terminals have been shut down due to new rules. Oil traders are on edge over concerns that an emergency order from the U.S. Department of Transportation this week requiring shippers to test all crude before it is carried by train could cut into deliveries of Bakken crude, as much as 800,000 barrels per day (bpd) of which is shipped […]