"Pipeline shipping costs remain lower than rail, and a lack of readily available tanker cars may create a bottleneck. The availability of tank cars may create a temporary "hiccup" in transport capacity, according to Tony Hatch, an independent railroad analyst in New York. Rail cars are "a pretty hot commodity," as a result of demand from oil producers in North Dakota, he said"
"Canadian Pacific Railway Ltd.'s shipments from North Dakota climbed to more than 13,000 carloads last year from about 500 in 2009, Ed Greenberg, a spokesman, said in an e-mail. The Calgary- based company has a similar plan in western Canada."
"During 2011, rail capacity in the region tripled to almost 300,000 barrels a day as higher production exceeded what pipelines handle, according to the State Department report on Keystone XL."