Terrorists seeking to attack the rail network have various options:
1. Bomb at the station.
2. Bomb on a passenger train.
3. Blowing up hazardous rail cargos in built-up areas.
4. Bomb on rail line, or other sabotage aimed at derailing a fast-moving train.
Go to the following link for an example of #4.
http://news.bbc.co.uk/1/hi/world/europe/8384404.stm
