Wreckage from the latest oil train explosion hadn’t yet been cleared from the crash site in West Virginia last week when President Obama vetoed legislation that would have  approved construction of the Keystone XL pipeline . The timing of the two events crystallizes one of the puzzles at the heart of the U.S. oil boom: How do we move all this new crude around the country? As production in the U.S. has soared to more than 9 million barrels a day—up from just 5 million back in 2008—the pipeline industry has scrambled to reorient itself around new oilfields in North Dakota and Texas. But railroads have proven more nimble and in many cases beat pipelines to the punch . The amount of crude being moved by trains jumped by almost 5,000 percent since 2009, even though trains are less efficient and typically more expensive than pipelines. Trains offer traders and energy companies something that pipelines don’t: flexibility.  With about 80 percent […]