Warren Buffett’s takeover of Burlington Northern Santa Fe is his biggest deal to date, and an affirmation that US railroads were an acquired taste for the billionaire investor.

Mr Buffett’s Berkshire Hathaway made its first investment in BNSF in 2007, paying $3bn for a 10.9 per cent stake in the Fort Worth, Texas-based company. But even as Mr Buffett added to his portfolio of rail stocks, the 79-year-old billionaire’s enthusiasm for the industry appeared to have its limits.