If you’re riding the Orange Line today, you may come across metrorail’s first ad-wrapped train car. And which advertiser will you see sprawled out on the side of the train car? McDonald’s. But don’t worry “Super Size Me” fans, you won’t see a Big Mac. Fries won’t be there either. It’s a healthier option: Locally, McDonald’s is working with Metro in their efforts to generate additional revenue as the first advertiser as they launch the…