We consider a collection of springs connected to one another and one end is fixed to a rigid support. If the spring at one end is pulled suddenly and released, the disturbance travels to the other end.
The reason behind this is when the first spring is pulled, it gets stretched. Due to elasticity, a restoring force is developed in the first spring.
This restoring force brings the first spring back to its mean position and streches the second spring and so on. Thus, the disturbance moves from one end to the other, but each spring oscillating about its equilibrium.