WordWeb Online

1. Cause to run off the tracks
   "they had planned to derail the trains that carried atomic waste"
    
2. Run off or leave the rails
   "the train derailed because a cow was standing on the tracks";
   - jump

Derived forms: derailed, derailing, derails

Type of: counteract, countermine, go, locomote, move, sabotage, subvert, travel, undermine, weaken

Encyclopedia: Derail