derail
Concise Oxford English Dictionary © 2008 Oxford University Press:
derail/dɪˈreɪl/
▶verb cause (a train) to leave the tracks.
■ obstruct (a process) by diverting it from its intended course.
– derivatives
derailment noun.
derailment noun.
– origin C19: from Fr. dérailler.
'derail' also found in these Oxford entries:

