To come to a dead-end.
Going nowhere; blocked.
A road with no exit.
A position that offers no hope of progress.
To come off the tracks.
To cause to deviate from a set course or direction.
To cause to come off the tracks.
To deviate from the previous course or direction.
An instance of diverting a conversation or debate from its original topic.
Synonym of derailer: A device placed on railway tracks in order to cause a train to derail.