CSX ( CSX) is enjoying some stellar performance this year. Shares of the $25 billion railroad have rallied more than 23% since the calendar flipped over to 2013, besting the broad market's otherwise impressive performance by more than double. CSX operates a huge rail network, with more than 21,000 miles of track spread across the Eastern U.S. The firm's main business is shipping coal, chemicals and intermodal containers. Unlike most transportation firms, rising energy commodity prices are arguably a good thing for CSX. That's because coal shipments make up close to a third of the firm's shipping capacity at any given time. And because rail is around four times more efficient per ton-mile than alternatives like trucking, railroad operators are less vulnerable to oil price volatility. That means that a move higher in energy prices wouldn't be a disaster for CSX (and other railroads, for that matter) like it would be for many of the firm's transportation sector peers. Post-recession, CSX has done a good job of improving its efficiency numbers -- and net margins currently weigh in the double-digits. Investors should expect to get a piece of that improved profitability. Right now, the firm pays out a 14-cent dividend for a 2.3% yield; I'd expect those numbers to increase in the next quarter.