Energy equipment maker Stewart & Stevenson Services Inc. said it has been awarded a $374-million contract to build trucks and trailers for the U.S. Army, extending an existing contract for one year. Stewart & Stevenson said it will deliver the contracted equipment, including 2,400 trucks and more than 500 trailers, between October 2002 and September 2003. The Army has extended an existing contract for a fifth year to the company's Family of Medium Tactical Vehicles (FMTV), the Houston-based company said.