off the rails

off the rails idiom
In an abnormal or malfunctioning condition, as in Her political campaign has been off the rails for months. The phrase occurs commonly with go, as in Once the superintendent resigned, the effort to reform the school system went off the rails. This idiom alludes to the rails on which trains run; if a train goes off the rails, it stops or crashes. [Mid-1800s]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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