Application of curves

Hi guys )
I have a question on the application of curves, as a spline … and as a guide for the movement of bot objects.
Let’s say the road, which is extruded from the model using a spline, and the ability to attach the movement of the machine to the coordinates of this curve (as an example).
In fact, there are much more examples of use, such as a gutter or rail … But I can’t figure out how to implement it.
Thank you in advance )

Following this :eyes: Grinding rail mechanic is definitely a need. Was thinking about splines and rope functions.