Before Berkshire Hathaway acquired BNSF in 2009, Warren Buffett concentrated his investment efforts on businesses that had "virtually no major capital requirements." See's Candy was a great example.
In 2007, Buffett called this his "dream business." He explained that the firm had produced close to $1.4 billion of earnings in the previous 35 years, with required capital investments of only $35 million. These high returns on invested capital type businesses made up the bulk of Berkshire's private and public business portfolio until the BNSF deal.