Movement on Curvy with MouseWheel

[staticdreams]

hi,
I'm trying to implement a manual movement of the camera along CurvySpline.
I'm already using a provided script with the package "MotorController.cs", which works great btw! Now I'd like to be able to control the movement using a MouseWheel.
Is this possible? Scrolling wheel backward would move the camera forward and scrolling forward would initiate the movement in the opposite direction. When the scrolling stops, the camera would also stop.
I tried duplicating "MotorController.cs" and substituting

Code:

float axis = Input.GetAxis("Vertical");

with 

Code:

float axis = Input.GetAxis("Mouse ScrollWheel");

but that doesn't seem to have any effect. Am I missing something or is there any other solution?

Thank you

[_Aka_]

This will help https://docs.unity3d.com/ScriptReference/Input-mouseScrollDelta.html