Full Disclosure: I work for Buffet’s Railroad.
Here is the non-logic of thinking Buffet would be mad if they built the pipeline(beyond the idea that people really think Obama cares what anyone thinks, including Buffet)...
If it is profitable to transport oil with trains now, and it is, it will still be profitable when a pipeline is built. On top of that as some have stated here, who is going to move the supplies to build the pipeline? That is right, rail roads.
Warren is going to make big bucks whether there is a pipeline or not.
When the pipeline capacity is built enough to bring the $30 differential in price down to $6~7 differential, it will no longer be profitable to pay $15 dollars to move it by rail. It will still be profitable to pay $5 to move it by pipeline.
The only reason the price differential exists, is a bottleneck in pipeline capacity. When it is built out, just like it has in every other place in the world, it will drop the differential.