Size aside, Berkshire Hathaway’s proposed acquisition of Burlington Northern Santa Fe railroad is about as typical a Warren Buffett deal as they come.

First, he was handed it on a plate. Mr Buffett owned 22.6 per cent of BNSF and was attending a board meeting when he dropped a hint to Matthew Rose, the chief executive, that he would be happy to acquire the rest. Like many chief executives in the same position would have done, Mr Rose leapt at the offer.