A Breather Switch (or Adjustment Switch) is a long diagonal gap in rail tracks created to allow for the transition between two segments of continuously welded rail, or at the transition between CWR and jointed track.

They have two advantages over traditionally joined track. Firstly, they eliminate or significantly reduce the noise and minor wheel damage created when a train passes over the small gap between jointed rails. Secondly, where a section of CWR is particularly prone to expansion, these act as relief points to ensure that under extreme circumstances track does not warp out of shape.