JUMP THE TRACK

{v. phr.} 1. To go off rails; go or run the wrong way. * /The train jumped the track and there was a terrible accident./ * /The pulley of the clothesline jumped the track and Mother's washing fell down./ 2. {informal} To change from one thought or idea to another without plan or reason; change the thought or idea you are talking about to something different. * /Bob didn't finish his algebra homework because his mind kept jumping the track to think about the new girl in class./ Compare: OFF THE TRACK.