The needle stop consists of a metal piece that is attached to a rail on a railway detour, and on which the "Needle (Railway)") needle of the point change will rest in order to transfer part of the load that a train exerts on the pointer when passing through the detours.

In the change, there is an area where the needle is not supported to allow its lateral movement. Whenever the change is traveled by a vehicle, transversal forces are produced due to the loop movement or the registration of the axles themselves when the change is placed on a deviated track. Since the gap between both support areas of the needle is large, with large bending moments, it is decided to use “needle stops”, which make contact with the needle, reducing the gap between the support points, and avoiding plastic deformation.