Truckload carrier operator Swift Transportation ( SWFT) said Wednesday that its second-quarter earnings rose 52.7% from the year-ago period. The company earned $45.5 million, or 60 cents a share, in the quarter, compared with $29.8 million, or 40 cents a share, a year ago. Second quarter results for 2006 and 2005 includes a $600,000 pre-tax benefit and a $507,000 pre-tax expense related to the interest rate derivative agreements. The second quarter 2006 result also includes a $4.8 million pre-tax benefit for the change in the company's discretionary match to the company's 401(k) profit sharing plan, as well as a $6.9 million benefit from improvements in its worker compensation claims management. Analysts polled by Thomson First Call were expecting earnings of $38.9 million, or 51 cents a share. Second-quarter operating revenue rose 1.9% from a year ago to $813.1 million. Excluding fuel surcharge revenue, net revenue fell 3.2%. The drop was primarily due to the reduction in average linehaul tractors. Analysts were expecting revenue of $824.8 million in the most recent quarter. Second-quarter operating income rose 41.6% from a year ago to $80 million, and operating margin was up 276 basis points to 9.8%. Revenue per tractor per week rose 3.7% to $3,106 this quarter compared with the period a year ago. Seperately, the Phoenix-based company said that its board has adopted a stockholder protection rights agreement in order to protect all shareholders against potentially abusive takeover tactics. Under the agreement, it declared a dividend of one right for each share of outstanding common stock.