directTrain(mons, brussel). 
directTrain(brussel, mechelen). 
directTrain(mechelen, antwerpen). 
directTrain(antwerpen, brussel). 

directTrain(oostende, brugge). 
directTrain(brugge, ghent). 
directTrain(ghent, brussel). 
directTrain(brussel, liege). 

directTrain(arlon, dinant). 
directTrain(dinant, namur). 
directTrain(namur, brussel). 
directTrain(namur, mons). 
directTrain(namur, liege).