Truck rental giant Ryder System (R) boosted first-quarter earnings expectations well above earlier forecasts as a result of a strong performance in its commercial rental unit.The company's shares were up more than 2%, to $39.15, in after-hours trading Thursday after closing the regular session up 37 cents, or 1%, to $38.24. The company said late Thursday it now expects to earn 52 cents to 54 cents a share, up from prior guidance of 36 cents to 39 cents a share. A Thomson First Call consensus estimate had expected the company to earn 39 cents a share in the quarter. A year ago, Ryder earned $19.8 million, or 31 cents a share, on revenue of $1.19 billion. The company attributed the improved forecast primarily to operations of its Fleet Management Solutions business segment, including better-than-anticipated contributions from two recent acquisitions and accelerated growth in commercial rental. The revised forecast had about a 5-cent-a-share benefit from certain acquisition-related expenses that were below their expected future run rates, as well as a restructuring credit. Miami-based Ryder will release first-quarter earnings on April 26.