Can a 150-year-old company be part of the modern economy? Apparently so. Union Pacific (UNP), America’s largest railroad, touches all parts of the economy, even globally — 30% to 40% of its shipments originate or terminate outside the U.S. — and it’s doing better than many younger firms: Its stock recently hit all-time highs. CEO Jack Koraleski, 62, has been working on the railroad his entire career. He’s an evangelist for the industry, especially stressing its eco-friendliness: A train can haul a ton of freight 500 miles on a gallon of diesel fuel, of which he buys over a billion gallons a year. He talked recently with Fortune’s Geoff Colvin about why Union Pacific is really an infotech company, the wisdom of hiring veterans, and much else. Edited excerpts: