A derailment is an accident on a railway or tramway in which a rail vehicle or part or all of a train leaves the tracks on which it is travelling with consequent damage and MOSCOW. An express train carrying hundreds of passengers from Moscow to St Petersburg has derailed killing at least 22 people and injuring dozens of others. This was the Nisqually of summer 07 where a freighter hit another in the crossover and blew down the hill lead power landed/went through the roa noun . 1. the act or process of derailing. 2. Psychiatry. loosening of associations. Tags: derailment, define, derailment, dictionary, Goods train derailed between Tinley Manor and Groutville stations on North Coast 28 February 2007 Derailment thought disorder - Wikipedia In psychiatry (also loosening of association asyndesis asyndetic thinking knights move thinking or entgleisen) refers to a pattern of discourse (in speech or // (de rlment) disordered thought or speech characteristic of schizophrenia and marked by constant jumping from one topic to another before the