The "Blue F-Train-Network" of the Epoch III has long been a legend: Already in 1951 fast long-distance trains could be found on the train time tables of the Deutsche Bundesbahnen. The stealth blue cars were eye-catching through their different colourful markings on the longitudinal beams. In the center of the wagon the raised silver DB letters were decorated. All “blue” trains, except two of them that operated in foreign countries, featured exclusively the 2nd class. The 2nd class of the three class classification was valid until the new class classifications in summer 1956 were implemented, and the old plush class was left out and replaced by the 1st class classification that is still valid until now. A metal plaque covered the class number 1 which was not always implemented consistently, as many photos of the wagons show.