DOW JONES NEWSWIRES Cummins Inc.'s (CMI) first-quarter profit more than doubled amid strength in key international markets and a recovery in the North American truck market. The company raised its current-year sales forecast by $1 billion, to $17 billion. It also expects earnings before interest and taxes of 14% of sales, up from its prior view for 13.5% The maker of truck engines and power-generation systems has seen earnings improve on higher sales of late, helped by strong demand in developing markets. But it and rivals have been squeezed of late by high commodity costs and expenses tied to increasing production. Cummins reported a profit of $343 million, or $1.75 a share, up from $149 million, or 75 cents a share, a year earlier. Revenue soared 56% to $3.86 billion. Analysts polled by Thomson Reuters most recently expected a profit of $1.44 on $3.61 billion in revenue. Gross margin rose to 24.8% from 24.3%. Sales in the engine segment--by far the largest--surged 68% from a year-earlier that was hurt by changes in emission standards and the economic downturn. Global heavy-duty truck shipments more than tripled, while medium-duty truck engine sales more than doubled. Shipments to construction markets were up 60% while mining shipments rose 59%. Component sales rose 47%, aided by recovery in Europe and growth in China and India, as well as emission-control products in North America. Shares closed Tuesday at $108.20 and were inactive premarket. -By Matt Jarzemsky, Dow Jones Newswires; 212-416-2240; matthew.jarzemsky@dowjones.com