Travelling through Germany is interesting at the moment because the different states have started to organise their own rail services: the process is similar to that of the UK in years gone by, but more locally decided.
We have a lot of new trains at the moment. The Stadler FLIRT is a popular choice for local companies which get a franchise. Locally they are operated by "Go Ahead" for the Baden-Württemberg government, which insists that the company paint them in a variation of the colours of the yellow and black state flag with the Baden-Württemberg lion. This example is a inter regional service in Karlsruhe:
The irony of new German trains getting a yellow end just as the UK stops using them is not lost on me.
Further north in Mannheim, a Deutsche Bahn version with the colour scheme used by several local authorities for their rail services. Local governments have a lot of control over local transport. They set and finance the service levels they want for bus, rail, metro, tram and occasionally ferry services, and tickets are for a region instead of a company, so one ticket covers all local public transport. In this case the cities of Mannheim and Ludwigsburg are on opposite sides of the river Rhine, and are in different states, so they have to work together to make transport services work.
Finally in Nordrhein-Westfalen , Abellio Rail (Dutch Railways) operate the units as S-Bahn (regional) and interregional trains. These are also the local colours with abstract drawings of local attractions on the side:
They have very bright interiors. Anyone with a hangover will probably want to walk:
Baden-Württemberg is a much more conservative state so we just get black and yellow...