NEW YORK (AP) -- Warren Buffett has made bets on railroads before, but now he's all in. The billionaire investor's Berkshire Hathaway Inc. on Tuesday agreed to buy Burlington Northern Santa Fe Corp., making a $34 billion bet on the future of the U.S. economy.

Burlington Northern, the nation's second-largest railroad, is the biggest hauler of food products like corn, and coal for electricity, making it an indicator of the country's economic health. The railroad also ships a large amount of consumer goods -- including items imported from Asia -- from big Western ports like Los Angeles and Seattle.

Analysts say Buffett is planting both feet in an industry that is poised to grow as the economy gets back on solid ground. It would be the biggest acquisition ever for Berkshire Hathaway Inc.

Berkshire Hathaway already owns about 22 percent of Burlington Northern, and will pay $100 a share in cash and stock for the rest of the company. That was 31.5 percent premium on Burlington Northern's Monday closing price. The stock shot up over 28 percent Tuesday, to $97.66 in afternoon trading.

Shareholders have the option to convert their stock for a cash payment of $100 per share or receive Berkshire Class A or Class B common stock. Up to 60 percent of the deal is cash and 40 percent is in stock.

"Berkshire's $34 billion investment in BNSF is a huge bet on that company, CEO Matt Rose and his team, and the railroad industry," Buffett said in a statement.

"Most important of all, however, it's an all-in wager on the economic future of the United States. I love