Though riders won’t see them for a few more months, the first of Amtrak's incoming 70 high-tech trains, built by Siemens, rolled off the assembly line and is ready to begin testing. “Our project goal was to make the supply chain as American as possible,” says Siemens Rail Systems president Michael Cahill of the $466 million initiative. Siemens is building parts in Norwood, Ohio, Alpharetta, Georgia and…