Samenvatting
This paper gives an idea of the proceedings concerning the design of the third train service (the R /A- trains) of the "Rail 21" plan of the Dutch railways. The premise is that the R /A train service is a part of the regional and suburban linking system. It is important to distinguish that transport on regional resp. suburban scale has different characteristics concerning speed, halt- density and frequency so much, that one must be careful mixing both functions. It is also important to practise reservedness in opening new stations, because of the desirable speed.