The "hang loose" sign with one hand, a big smile and aviator glasses: you just can't miss tram driver Peter Wirth. Known as the "Bahnbabo," or in English, "tram boss," he's a local institution in the western German city of Frankfurt. The city's coolest tram driver, who has been a hobby bodybuilder for 36 years, doesn't just show off his big muscles - he puts them to use. He gets out of the driver's seat and helps people with bags and luggage, and walks through the car chatting up passengers of all ages.