Trams in Frankfurt are identified by an ongoing series of letters. For example, the latest type of tram, the second low-floor tram in Frankfurt, has the letter ‘S’. There are currently K-type (Ebbelwei-Express), R-type and S-type vehicles in service. All of these trams have low floors apart from the historic ‘Ebbel Ex’. Many older types of vehicles can be seen in the Transport Museum.