I make here a summary of the possible train tickets for longer or
shorter distance..
Campus card (5fixed round trips, you need to buy a recharge after
these 5, and the price is function of the distance)
Key card (from anywhere to any place no more than 20km away..) 17
euros for 10 trips
Go pass ( from anywhere in belgium to anywhere in belgium, from south
to north, from west to east, ..) 50 euros for 10 trips
here is the site of b-rail
http://www.b-rail.be/nat/E/tarifs/passes/index.php
and for campus
http://www.b-rail.be/nat/E/tarifs/traincards/campus/index.php
if you have more question just post on this subject ;D