Union Pacific Corp. said Thursday that third-quarter profit rose 83 percent on a reduced tax liability and higher revenue, but analysts said the company must follow its competition and improve infrastructure to keep profits up.

Net income for the largest U.S. rail freight carrier grew to $369 million, or $1.38 per share, for the three months ended Sept. 30. That was up from $202 million, or 77 cents per share, a year ago.

Excluding reduced income-tax expenses, the company reported a profit of $251 million, or 94 cents per share, for the most recent quarter.

Revenue rose 13 percent to $3.46 billion in the most recent quarter, with commodity revenue up 12 percent. Agricultural and industrial products led the increases, up 27 percent and 16 percent, respectively. Carload volume grew 1 percent to 2.4 million loads from a year ago.

Union Pacific shares closed down 63 cents to $68.12 Thursday on the New York Stock Exchange.