Valero Energy Corp. has released its financial results for the first quarter, reporting record operating income for its ethanol segment, despite production slowdowns caused by weather-related challenges in transporting ethanol by rail.

Overall, Valero reported net income attributable to stockholders of $828 million, or $1.54 per share, up from $654 million, or $1.18 per share, for the same period of 2013. First quarter operating income was $1.4 billion, up from $1.1 billion for the first three months of 2013.

The company’s refining segment earned operating income of $1.3 billion during the quarter, up slightly from $1.2 billion during the first quarter of the previous year.

The ethanol segment earned $243 million in operating income during the first quarter, up significantly from the $14 million in operating income reported for the same period of 2013. Valero attributed the increase to higher gross margin per gallon driven by weather-related supply disruptions, as well as lower industry ethanol inventories, import volumes, and corn costs relative to the first quarter of the prior year.

During a call to discuss the results, Ashley Smith, vice president of investor relations at Valero, noted the company’s ethanol production volumes averaged 3.1 million gallons per day during the quarter, a slight reduction compared to the final quarter of 2013. Smith attributed the drop in production to slowdowns created by weather-related rail congestion. Moving into the second quarter, Smith said ethanol production is expected to average 3.5 million gallons per day.

Smith also addressed Valero’s recent acquisition of a 110 MMgy ethanol plant in Mount Vernon, Ind., from a subsidiary of Aventine Renewable Energy Holdings Inc. He said that Valero acquired the facility for $34 million and noted that efforts are underway to restart the facility. The plant is expected to resume operations during the third quarter, he said.