July 23 (Reuters) - Norfolk Southern NSC.N beat Wall Street expectations for second-quarter adjusted profit on Thursday, as stronger freight demand and increased fuel surcharges billed to customers helped counter fuel-cost pressures.

Fuel costs have remained a headwind for transportation companies, though railroads have partly offset the pressure by passing costs to shippers via fuel surcharges, operational efficiencies and steady intermodal demand.

Here are more details:

• U.S. gasoline prices topped $4 a gallon in March for the first time in more than three years and have remained near that level, keeping pressure on fuel-intensive industries.

• Atlanta, Georgia-based Norfolk reported an adjusted profit of $3.52 per share, compared with $3.29 per share a year earlier. Analysts expected an adjusted profit of $3.31 per share, according to data compiled by LSEG.

• The company's railway operating income for the second quarter rose 11% to $3.5 billion from a year earlier.

• On an adjusted basis, the company's operating ratio - a key measure of efficiency - was 65.5% for the quarter, deteriorating by 210 basis points from a year earlier.