It happens to every company sooner or later: Wall Street sets a mark for quarterly earnings, and the company misses that goal. Sometimes an earnings stumble is a signal to sell, but digging in the dirt is also a good way to find turnaround candidates while they're getting beaten down. Today, we'll take a virtual tour around the Americas, starting at a desolate railyard in Virginia, going down to an empty mineshaft in Peru, and finally landing on flat rock in Florida. Tickets, please!

Norfolk Southern
Our first underperformer today is NorfolkSouthern (NYSE:NSC), one of the four major railroad operations left in the United States after the consolidation at the end of the last millennium. Norfolk Southern was left grasping for the last 3.3% of the earnings that Wall Street analysts had expected it to pull out, with $0.89 of GAAP earnings per diluted share where $0.92 should have been. Revenues came in right on track, at $2.39 billion.

That total sales number was 11% higher than that of last year's comparable period -- not too shabby for a long-established business like railroading. It certainly puts East Coast rival CSX (NYSE:CSX) to shame. The earnings miss rested on the loss of tax credits related to synthetic fuel usage, which in turn results from higher oil prices. It didn't help that the mainstay coal business only grew by a measly 1% from last year, but nonetheless, most of the problem here is clearly out of Norfolk Southern's control.

The Conrail chop job is well in the past by now, and with gas prices sky-high, you might expect the railroads to steal some business from truck lines. That's where I'd expect any future growth to come from, so a bet on Norfolk Southern or its rivals is a bet on oil prices in my book, particularly since the price level is already so high that synfuel tax credits have been largely eliminated. Adjust expectations accordingly.

Peru Copper
Moving on to our next disappointing performer, we're looking at Southern Copper (NYSE:PCU), the artist formerly known as Southern Peru Copper. This massive copper miner missed the average analyst earnings forecast of $3.09 per share by a slim 3.6% margin, as it could only muster $2.98 per share. Gross sales stopped at $1.28 billion, also below analyst expectations of about $1.32 billion. While slightly below estimates, those numbers represent sales growth of 34% over last year, and 41% higher earnings.

This stock first caught my eye about a year ago, as I was screening the stock exchanges for promising dividend payouts. This one looked too good to be true, so I passed it over without going into all the detail I could have. By early May this year, the share price had doubled from when I first saw it, and the dividend yield was still about 8%. That boogie beat you hear is the sound of missed opportunities.

Back to the recent report, though. Southern Copper operates several mines on behalf of GrupoMexico, and the workers at one of those mines went on strike in March, hurting the volume output of copper and molybdenum for the quarter. That shortfall was very nearly made up for by higher copper, silver, and zinc prices, as the upward pricing trend of the past couple of years seems to continue unabated.

Assuming that copper prices don't suddenly drop through the floor -- and your guess is as good as mine there -- the next quarter should see higher revenues and earnings, because the labor issues have been resolved and the affected mine should reopen shortly. I wish I had a firmer idea of where raw material pricing might go in the future, because Southern Copper still looks mighty tempting to me.

Florida Rock
Let's rock out to close this whirlwind tour, shall we? The featured band here is Florida Rock (NYSE:FRK), a business based on building materials like concrete blocks, gravel, and ready-mixed concrete. Sales were up 15% year over year to $361 million, and GAAP earnings per diluted share of $0.87 missed the $0.95 analyst target by 8%.

It stands to reason that the widely reported housing construction slowdown should hurt Florida Rock as well, since it provides plenty of materials to that sector. The miss wasn't all that bad, and it's hard to get too upset over a 27% bottom-line boost year over year. Strong product pricing nearly compensated for 9.5% lower cement volume.

Management comments make the nonresidential market sound strong, and the positive pricing effects only had one month in which to make an impact on the just-completed quarter. I believe that the market punished Florida Rock too harshly over this report; the share price dropped by more than 12% overnight. Florida Rock is a solid business with great pricing power, and I think it will see some strong growth from here. Eventually, the share price should follow.

Some of these underperformers are victims of larger circumstances, while others might have only themselves to blame. It's up to you to decide which down-on-their-luck companies should be able to pull themselves up by the bootstraps, and which really are stuck in the mud. Come back next Monday, and we'll take a look at another batch of mishaps and disappointments. It'll be fun and educational. Promise.

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Fool contributor Anders Bylund holds no position in the companies discussed this week. Did you know that he once worked on the railroad? Yes, desk jobs count. The Fool has a disclosure policy, and you can see Anders' current holdings for yourself.