It would seem to me that Buffet and the railroad have a problem of too much business for the available track and equipment.
The pipeline will solve his problem. He probably lacks the capital to increase his capacity that would always be threatened by the possibility of the pipeline
BNSF oil terminals are greatest in the Bakken area. I don’t see the Canadian Oil Sands have as great an impact for the railroad that Buffett’s Berkshire Hathaway owns.
Keystone XL would not even enter North Dakota. They really focus on separate areas. Some overlap, but it is minor.