Belgium has one of the best train system in Europe. Trains are frequent, clean, on time and the network is wide and comprehensive. Do not waste money on a 1st class ticket in Belgium.
Discounts up to 60% or more are available in the forms of weekend, youth, senior, go pass, multi-pass rates. Children under 6 travel free. Up to 4 children age 6 to 12 travel for free after 9:00am on weekdays if accompanied by an adult.
Day trips by train from Brussels are fast, easy and inexpensive. Bruges: 1hr, every 30', $10 RT. Ghent: 30', every 10'. Antwerp: 1hr, every 10-15'. Paris: 2hrs 30' on Thalys, every 30'-1hr, . Amsterdam: 2hrs 30' on Thalys, 3hrs on regular trains.
For more details, visit the SNCB at http://www.b-rail.be.