RB 51 is the designation of several regional rail services in Germany:
, operated by agilis between Neumarkt (Oberpfalz) and Plattling , operated by DB Regio Mitte between Frankfurt (Main) and Wächtersbach , operated by DB Regio Mitte between Neustadt (Weinstraße) and Karlsruhe , operated by DB Regio NRW between Enschede and Dortmund , operated by DB Regio Südost between Dessau and Falkenberg (Elster) , operated by Ostdeutsche Eisenbahn between Rathenow and Brandenburg
See also Red Baron (aircraft)