Night train from Offenburg to Cologne
There currently are a variety of options to travel by night train from Offenburg (Germany) to Cologne (Germany), taking between approximately 4 and 7 hours: Namely the IC 60402 and the ICE 100. These lines are operated by DB.
Deutsche Bahn (DB) exited the actual night train business in 2016. However, it operates around a dozen Intercity and Eurocity trains that run exclusively at night. These trains only have first and second class seats. The cars remain lit throughout the night and the seats cannot be reclined.