Norfolk Southern Corp, the No. 4 U.S. railroad, on Monday reported slightly lower fourth-quarter profit due partly to a 15 percent drop in coal revenue. The Norfolk, Virginia-based company said gains in its intermodal, or consumer goods shipments and its merchandise segment that includes chemical and agricultural goods, largely offset the fall in coal revenue. Norfolk Southern said the drop in coal was caused by a weak global export market and fewer shipments of coal to utilities, which resulted in a decrease in freight volumes of 6 percent. Overall, freight volumes on the railroad were up 4 percent during the quarter. Norfolk Southern reported fourth-quarter net income of $511 million, down from $513 million a year earlier. Earnings per share were flat at $1.64. Analysts expected $1.63. Revenue also remained flat at $2.9 billion and came in below analysts’ expectations of $2.94 billion. The company also received a boost from falling oil prices. Its fuel bill for the quarter fell nearly 14 percent to $347 million from $403 million. In light premarket trading, Norfolk Southern shares were down nearly 1 percent at $104.00.