The derail was placed deliberately so that the train would fall into the river.
A Derail or Derailer is a device used to prevent fouling of a track by unauthorized movements of trains or unattended rolling stock. It works (as the name suggests) by derailing the equipment as it rolls over or through the derail
run off or leave the rails; "the train derailed because a cow was standing on the tracks" cause to run off the tracks; "they had planned to derail the trains that carried atomic waste
If a train is derailed or if it derails, it comes off the track on which it is running. Several people were injured today when a train was derailed No-one knows why the train derailed
cause to run off the tracks; "they had planned to derail the trains that carried atomic waste
run off or leave the rails; "the train derailed because a cow was standing on the tracks"
A track safety device designed to guide a car off the rails at a specific spot as a means of protection against collisions or other accidents
A device placed over the rail to prevent a car from rolling out of a siding (for example) and onto the main line
To derail something such as a plan or a series of negotiations means to prevent it from continuing as planned. The present wave of political killings is the work of people trying to derail peace talks