WASHINGTON, US - Billionaire investor Warren Buffett said Tuesday his Berkshire Hathaway company will purchase Burlington Northern railway for 44 billion US dollars (S$61.7 billion), calling the move a "huge bet" on the American rail system.

"Our country's future prosperity depends on its having an efficient and well-maintained rail system," said Buffett, Berkshire Hathaway's chairman and chief executive officer, adding that the deal was the biggest ever for his storied investment fund.

A company statement said the purchase of the Burlington Northern Santa Fe Corporation (BNSF) for 100 dollars per share was valued at some 44 billion dollars.

"America must grow and prosper for railroads to do well," Buffett said, adding that "the investment in BNSF is a huge bet on that company... and the railroad industry."

Buffett suggested that the purchase is something of a gamble, but one he is certain will pay off.

"It's an all-in wager on the economic future of the United States. I love these bets," said Buffett, known in financial circles as the "Oracle of Omaha," for unparalleled investing acumen that has made his fund one of the most successful US companies.

Burlington Northern president and CEO Matthew Rose said he company was equally excited by the deal.

"We are thrilled to have the opportunity to become a part of the Berkshire Hathaway family," said Rose.

"We admire Warren's leadership philosophy supporting long-term investment that will allow BNSF to focus on future needs of our railroad, our customers and the US transportation infrastructure.

Rose added: "This transaction offers compelling value to our shareholders and is in the best interests of all of our constituents including our customers and employees."