I just stumbled on this article, "The McTrain: The Rise and Fall of McDonald's Ambitious Plan to Conquer the Railroads", written a few days ago. I am a fan of dining cars, as well as rail cars and trolleys that have been converted to "diner" restaurants, but this one is a first for me.
The article describes how the Deutsche Bundesbahn (German Federal Railroad) retrofit two dining cars to serve McDonald's food. Apparently, the power consumption was unbelievably high. The dining cars lasted from 1992-1995. The article is well-illustrated and, if you read German, there are links to more information on German forums.
Tomlinson Run Railroad