Amtrak has recently released a new design for its old engines — a design which promises to cut diesel exhaust by 50 percent. The first new retrofitted locomotive is scheduled to patrol the tracks between San Jose and Sacramento, and is already being called the cleanest passenger train in California. By revamping their old engines rather than purchasing new ones, Amtrak was able to save over $2 million an engine. Let's hope this is a green sign to come for the train industry on the whole.