On May 22, Union Pacific Railroad will launch a satellite and Web technology combination making it easier to follow the progress of "Challenger" No. 3985, the world's largest operating steam locomotive, during its 10-state, 4,400-mile tour. Global Positioning Satellite (GPS) transmitter was installed on one of the railcars that will travel with Challenger. The GPS system has been integrated with a map on UP's Web site at www.up.com. Enter the numbers "3985" in the search box on the homepage for a shortcut to the map. Web site visitors will be able to access route maps with varying amounts of detail. The GPS system will update the map every 15 minutes showing Challenger's location.