With truck sales expected to drop as a result of EPA's rule for cleaner-running heavy-duty diesel engines now in effect, Columbus, IN-based diesel engine maker Cummins Inc. is taking cost-cutting measures to avoid layoffs.

Cummins is reducing overtime, cutting its temporary work force and making plans for plant shutdown days, The Associated Press reported.

Moody's Investors Service downgraded Cummins' debt outlook from "stable'' to "negative,'' citing market uncertainties caused by the more stringent emissions standards. However, analysts with Moody's said recent restructuring by Cummins should help it remain competitive.

Company officials say layoffs are possible in coming months if engine demand remains soft. Cummins has nearly 25,000 employees worldwide.

Meanwhile, Detroit Diesel said it has seen orders drop and will only need to produce 50 to 60 of its EPA-compliant engines a day when production resumes on October 28. The engine maker said in August that about 700 workers, or 45% of those employed in the manufacture of heavy duty, on-highway trucks, will be laid off.

Engine maker Caterpillar Inc. and truck makers Paccar Inc. and Navistar International Corp have also announced layoffs.