From Longman Dictionary of Contemporary Englishgo off the railsgo off the railsinformalSSSC to start behaving in a strange or socially unacceptable way At 17 he suddenly went off the rails and started stealing. → rail
Examples from the Corpus
go off the rails• But it was the news pages that had really gone off the rails.• Has something gone off the rails here?• Things started to go off the rails, however, with the Fiat Multipla. 