(Reuters) - U.S. railroad operator CSX narrowly beat second-quarter profit estimates on Monday, helped by higher shipment volumes and robust pricing, sending its shares up 5% after the bell.

Improving intermodal volumes, or goods moved via two or more modes of transport, have helped railroads squeeze out profits along with higher-than-inflation pricing, even as the overall freight industry continues to face a downturn.

CSX's revenue from intermodal shipments was $506 million in the reported quarter, 3% higher than a year ago.

The Jacksonville, Florida-based company reported revenue of $3.7 billion in the second quarter, in line with analysts' estimates.

It reported a profit of 49 cents per share, above analysts' estimate of 48 cents per share, according to LSEG data.

Its operating margin was 39.1% for the quarter, down 50 basis points from a year earlier.

CSX's east-coast competitor Norfolk Southern ( NSC ) also reported second-quarter profit above estimates last month, helped by higher pricing.