Union Pacific reported a fourth-quarter profit on Thursday that rose 7% on the back of higher grain and fertilizer shipments and core pricing gains, sending the railroad operator's shares up more than 4% before the bell.

Union Pacific’s profits rose in the fourth quarter as volume increased 5% and operating costs fell. “Our strong fourth quarter results represent a great capstone to a very successful year for Union Pacific,

Union Pacific on Thursday posted a better-than-expected profit for the fourth quarter helped by improving volumes and robust pricing, which was partially offset by lower fuel surcharge and less profitable cargo mix.