Cummins Inc. said today (Oct. 30) third-quarter net income fell 59% from a year ago as it sold fewer engines for heavy-duty trucks and recreational vehicles.

But Cummins’ profit outpaced Wall Street’s forecast, and two of the company’s units returned to profitability after losing in the previous quarter. The engine maker also said sales would be slightly better than it had previously forecast, according to MarketWatch.

The Columbus, Ind. manufacturer said demand increased in engine and components sales to the medium- and heavy-duty truck engines markets in the U.S. compared to the second quarter in advance of new emissions standards that take effect in January 2010.

But, based on current orders, the company expects very low demand in these markets during the first half of 2010.

Cummins shares rose 6% to $48.51 in early trading.

The stock has surged 81% this year.

Net income was $95 million, or 48 cents a share, compared to net income of $229 million, or $1.17 a share, in the year-ago period.

On an adjusted basis, Cummins said it earned 56 cents a share. Analysts had forecast 37 cents a share, according to Factset Research.

For the year, the company raised its guidance for sales to be slightly less than 30% below 2008 levels, compared to its prior forecast of sales declining by more than 30%