Analysis of information sources in references of the Wikipedia article "프랑크푸르트 U반" in Korean language version.
The Frankfurt "U-Bahn" is not a real metro, but rather a typical German Stadtbahn (like that of Stuttgart, Dortmund or Hanover), i.e. some sections in the city centre were built to full metro standards, whereas others along outer sections have level crossings, in the case of line U5 even some on-street running.
