Definition

1. Verb (transitive):

   • To cause (a train or other rail vehicle) to leave its tracks accidentally: This is the primary meaning, referring to the action of making a train come off the rails.
   • To cause (a process, plan, or discussion) to go off course or fail: This is a figurative extension, meaning to disrupt or prevent something from continuing as intended.

2. Verb (intransitive):

   • (Of a train or other rail vehicle) To leave the tracks accidentally: This describes the event itself happening to the rail vehicle.

Usage Examples

• Verb (transitive - literal):

  • The vandal attempted to derail the freight train by placing debris on the tracks.
  • A collision with a truck at the level crossing could derail the passenger service.

• Verb (transitive - figurative):

  • The senator's scandal threatened to derail the entire legislative agenda.
  • We must not let this minor disagreement derail our negotiations.

• Verb (intransitive):

  • The locomotive derailed just outside the station, causing major delays.
  • Investigators are determining why the subway car derailed.

Advanced Usage

• "to be derailed": (often passive voice) to be caused to leave the tracks or to be thrown off course.

  • The peace talks were derailed by a sudden outbreak of violence.
  • Several cars were derailed in the accident.

• "to derail from": (less common) to cause to deviate from a path or course. This phrasing is more typical in figurative use.

  • The constant interruptions derailed the speaker from her main argument.

Variants and Related Words

• Derailment (n): The event or instance of a train coming off the tracks, or the figurative disruption of a process.
  • The derailment was caused by a broken rail.
  • The project suffered a major derailment after the key investor withdrew.

Synonyms

• Literal: Throw off the tracks, run off the rails.
• Figurative: Disrupt, sabotage, thwart, sidetrack, hinder, obstruct.

Related Phrasal Verbs/Phrases

• Derail from (phrasal verb): To cause someone or something to deviate from an intended path, topic, or course of action. (Note: This is a less common but valid construction, primarily figurative).
  • He kept asking unrelated questions to derail the discussion from the main issue.

Related Idioms

• "To throw a spanner in the works" (UK) / "To throw a wrench in the works" (US): This idiom is a close figurative synonym for "derail," meaning to cause a plan or process to fail.
  • The sudden budget cut threw a wrench in the works for our expansion plans.

Verb

1. run off or leave the rails
   • the train derailed because a cow was standing on the tracks
2. cause to run off the tracks
   • they had planned to derail the trains that carried atomic waste