There's a saying that a rising tide lifts all boats. It must lift all railcars, too, considering that Union Pacific (NYSE:UNP), one of the worst-run railroads in terms of operational and financial statistics, has seen its stock match that of the average major railroad over the past 12 months.

Looking at fourth-quarter results, you can at least find signs of progress. Total operating revenue climbed 13% in the quarter, a boost composed mostly of a 1% increase in carload volumes and an 11% increase in revenue per car. That doesn't sound like a bad performance, but we'll need to wait and match that up with rivals such as CSX (NYSE:CSX), NorfolkSouthern (NYSE:NSC), and Burlington Northern Santa Fe (NYSE:BNI).

Moving on, the company did improve its operating ratio slightly, and the operating margin for the quarter came in at 14.7%, vs. 14% a year ago. Operating earnings rose 18% for the period, and net income climbed 25% after the year-ago number was adjusted for an asbestos-related charge.

My hunch on Union Pacific's stock is that investors are already assuming some measure of success in the company's efforts toward an operational turnaround. The company can certainly do more to reap better fuel-cost recovery, improve operating performance, and get more out of the intermodal business.

Pricing, too, might be a potential source of strength. The company has traditionally tried to compete on price, and some of those below-market contracts should begin to roll over. Remember, rail shipping is not only more fuel-efficient than trucking -- and that's important in this time of high gas prices and fuel surcharges -- but also, on the whole, meaningfully cheaper than trucking.

I can see reasons to be optimistic on Union Pacific. Coal demand is strong, the American auto business probably can't get too much worse, and there's a new CEO leading the show. All that said, this company is still a far cry from the likes of Canadian National (NYSE:CNI) and Burlington, and its return on capital seems to be well below its cost of capital. That's not a formula for long-term success. So while Union Pacific may continue to ride along with the rest of the railroads, I'm not getting aboard until I see better results.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).