“Interior view of the 3rd class, 1913” German Railcar

The German transport company Hochbahn, in their article on the history of Hamburg's first subway line, describes the interior design of the carriages as “divided into 2nd class with dark green imitation leather seats and 3rd class with polished mahogany - 1st class would have been reserved for the Emperor and was therefore not even counted" (Hochbahn.de). 

In this image we see the interior of one such car, specifically a third-class carriage. Some parts of the design seem intended to make the space more welcoming and inviting, such as the curtains and lamps, almost making it feel home-like, but other parts of the design, like the structural poles and numerous advertisements, are clear indications of this space as a public, industrial space. 

Hochbahn's article also describes the exterior design of these rail cars as follows: “From the outside, the 3rd class could be identified by its yellow paintwork and the 2nd class by its red paintwork. The class division was not abolished until the end of 1920.” 

The use of color-coding in primary colors to separate the 2nd and 3rd class areas is an interesting design strategy for communicating visual information to a passenger.