CSX generated $US679 million of revenue from hauling coal for the year, a 9% fall from the $747 million clocked up in 2012.

Overall, the coal division weighed down CSX’s annual results, with the company increasing its total revenue by 5% in 2013 to $3.03 billion.

In terms of the December quarter, CSX hauled a total of 32.5 million short tons – 5% down year on year.

However, the export volumes were up 6% year on year to 10.2Mt.

CSX credited the declining volumes to a fall in domestic shipments due to continued low gas prices and utility stockpiles, which remained above target levels.

CSX shares fell nearly 7% last week since the fourth quarter results were released on Wednesday, with a public holiday preventing further trading on Monday.

"Supported by the strength of an expanding economy, we delivered 6% volume growth in the quarter, despite another sharp decline in coal," CSX chairman, president and CEO Michael Ward said in the Q4 results.

"As the economy continues to expand, CSX is well positioned to leverage that environment to create sustainable long-term value for our customers and shareholders."