Warren Buffett's Berkshire Hathaway Inc. plans to increase capital spending at its railroad to about $4.1 billion this year as it prepares to handle rising oil shipments and expands intermodal terminal capacity.The 2013 proposal includes $2.3 billion on the core rail network and about $1 billion on locomotive, freight car and equipment purchases, BNSF Railway Co. said in a statement Friday.The Fort Worth-based unit is also spending about $250 million on a U.S. rail safety mandate and $550 million on terminal, line and intermodal expansion and efficiency projects.The plans are designed to add capacity for industrial product shipments related to the Bakken shale oil formation in the northwestern U.S., it said.CEO Matt Rose said this month that BNSF will spend "a couple hundred million dollars" on capital improvements to haul more petroleum to refineries from the formation. He expects the railroad to boost crude oil shipments 40 percent this year."This record capital plan continues our long-term focus on ensuring our network is prepared for the growing U.S. demand for freight rail," Rose said in the statement."We are focused on investing to meet our customers' expectations and to expand capacity where growth is occurring."BNSF spent $3.6 billion on capital investments last year, it said.