CSX said the railroad's earnings per share actually increased 2 per cent because it had fewer shares outstanding.
The Jacksonville, Fla.-based railroad made $455 million, or 44 cents per share. That's down from $464 million, or 43 cents per share in the same period a year ago.
Revenue fell 2 per cent to $2.89 billion as the mix of goods it carried changed. Total volume was down about 1 per cent.
Analysts surveyed by FactSet expected CSX to report earnings of 43 cents per share on $2.94 billion revenue.
Freight railroads' results are watched closely because the number of carloads of goods they carry offer clues about the health of the nation's economy. CSX is the first major railroad to report.
CSX said strong increases in shipments of export coal, automotive shipments and intermodal containers helped offset weak demand for coal from domestic utilities.
CSX hauled 29 per cent less coal domestically in the quarter, but saw a 25 per cent jump in its export coal tonnage. Overall, CSX hauled 36.3 million tons of coal in this year's quarter, down from 43.3 million tons in 2011.
"CSX continues to respond well to moderating economic conditions and challenges in our domestic coal business," said Michael Ward, CSX's chairman, president and CEO.
Throughout 2012, coal demand has generally been weak because of last year's mild winter and some utilities' shift from burning coal to cheaper natural gas.
CSX officials said they still expect 2012 earnings to improve over last year. Through the first nine months of 2012, CSX reported $1.41 billion net income, or $1.36 per share. That's four per cent higher than last year's $1.37 billion net income, or $1.24 per share.
CSX, based in Jacksonville, Fla., operates over 21,000 miles of track in 23 eastern states and two Canadian provinces.
Union Pacific Corp., the biggest railroad in the U.S., will release its third-quarter results on Thursday.
CSX shares rose nearly 2 per cent to $22.01 in after-hours trading.
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CSX Corp.: www.csx.com