 Lines 3 and 4, since the construction of temporary platforms at the Severinstraße station while the actual station gets modernized and connected to the North-Southern tunnel, are Cologne's first HF lines completely equipped with level entrance.The western branch of Line 5 still has a two stops (Subbelrather Straße/Gürtel and Nußbaumerstraße) with low platforms, the rest of its stations were made high-floor when the line was extended into the Butzweilerhof industrial area.Line 13 is also called the "beltway" ("Gürtel") line because it is the only line that does not touch the city center.