What's happening: Nearly 70 Greyhound buses, owned by Naperville-based Laidlaw International Inc., have been operating non-stop since Wednesday when the evacuation of the New Orleans Superdome began. Why: Tens of thousands of people are stranded and Laidlaw is one of the biggest bus companies in the country. Before the storm: Laidlaw, which has 65,000 employees nationwide, got into financial trouble in the late 1990s and emerged from bankruptcy two years ago. It has since focused operations on busing--some city systems, its 40,000 school buses and Greyhound--with better results. Profit for the nine months ended May 31 totaled $296 million, up...