Warren Buffett has built his reputation as the modern world’s greatest investor as much for what he hasn’t done as for what he has. His contrarian decision to steer clear of the tech mania that gripped the world around a decade ago is as significant as his famous investments in strong consumer franchises such as Gillette and Coca-Cola.

So what he does with the money he manages has a far wider significance than the actions of less celebrated money managers.

Two of Buffett’s latest buys are in sectors that are so clearly old economy: railways and coal. The investment star is ready to pay $26 billion in stock and cash to buy Burlington Northern Santa Fe Corp. Analysts have also pointed out that the company Buffett is eyeing is not a pure railroad play. It also has tracks and rights of way near some very lucrative and low-sulphur coal near the west coast of the US.

Buffett has his fair share of critics. Financial blogger Barry Ritholtz has in a recent post attacked Buffett’s decision to team up with Goldman Sachs to buy tax credits from Fannie Mae—a mortgage lender that was bailed out by the US government last year with taxpayer funds. The US treasury shot down the proposal. Ritholtz said, “This paper transaction would have provided precisely zero value to...taxpayers.”

“For Warren Buffett’s Berkshire Hathaway to team up with Goldman Sachs (which he now owns a healthy chunk of) is a bit of a revelation: We have been spun by his genteel manner, his aw shucks down-home-isms, his off Wall Street, less bloodthirsty approach to investing, into somehow believing he was different,” thundered Ritholtz.

But that does not mean Buffett’s recent move into railroads is any less interesting. That the sage of Omaha has spotted opportunities in two industries which were dismissed as being in terminal decline not too long ago, may tell us something about how their economics could change.

Buffett wrapped a patriotic flag around himself when he tried to justify his interest in the railroad as a bet on the US recovery. But businessmen in India who have interests in infrastructure already know that you can make a killing by owning a road or airport.

That’s one area where they are one step ahead of Buffett.

How does one make sense of Buffett’s latest interest? Tell us at views@livemint.com