The study of the graphic skin for the exterior of the railroad carriage was developed emphasizing the simplicity of the language to facilitate a better visibility of the sliding doors.

 The sign is, as well as aesthetic quality, an important visual reference of a more efficient communication system in relation to the use, to the people and to the perception of the oncoming train while people stand on the platform. Doors are highlighted by basic graphic signs, but at the same time they are strong and of great impact, in order to be easily visible even in conditions of congestion and overcrowding.