A plummeting U.S. dollar may not be a terrible thing, but I'm willing to bet that sort of sentiment won't play well in Peoria these days.

The Illinois city is the headquarters for Caterpillar (NYSE: CAT). Thanks in part to international sales helped by the languishing dollar, the construction-equipment manufacturer handily outdid expectations for its March-quarter earnings. The company earned $922 million, or $1.45 a share, for the period. That represents a 13% increase from its $816 million, or $1.23 a share, in net income for Q1 2007. Perhaps more importantly, the per-share figure topped analysts' expectations by more than a dime.

The company's stellar performance saw all three of its major segments -- machinery, engines, and financial products -- expand their revenue by 16% to 22%. According to CEO Jim Owens, Caterpillar's overall sales increase was tied to "... robust demand for products used in the global mining and energy industries and for machines used by our customers to build infrastructure, particularly in emerging markets." He also called the company's record results "a remarkable testament to our global strength ..."

But while management reaffirmed expectations for EPS growth of 5% to 15%, based upon expected sales growth of 5% to 10%, it was less sanguine about prospects for the U.S. and European economies, halving its expectations for full-year U.S. economic growth to 0.5% and lowering its growth expectations for Europe, as well.

Caterpillar thus becomes the latest in an already lengthening string of big U.S.-based companies to check in with solid overall results in the face of a weakening U.S. picture. The company's earnings were reported the same day that Honeywell (NYSE: HON) reported a strong tailwind from overseas operations. And earlier, big companies including  Coca-Cola (NYSE: KO) and  IBM (NYSE: IBM), rode solid performances abroad to strong quarterly results.

As for Caterpillar, I continue to believe that its reasonable 14.4 forward 2008 P/E, its 1.7% yield, and its key role in the industrialization of much of the developing world all earn the company a spot on the radar screens of Fools interested in solid heavy industry investments.

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Fool contributor David Lee Smith hasn't been to Peoria, and he doesn't have financial positions in any of the companies mentioned. He does welcome your questions, comments, or barbecue sauce recipes. The Fool has a disclosure policy.