It will need mains voltage connecting somewhere for the sockets to work, but the photos don't show which wire connects to where or where the incoming supply needs to connect.
Note also that some of the bare contacts on the fourth photo will be live at mains voltage if it is connected up, and therefore highly dangerous if accessible. When fitted in the train this would have been against the wall and therefore inaccessible, so you need to do something similar or cover the back in some other way.
I suggest you get advice from a professional electrician.