How the Train Pantograph goes automatically up and down?

Here s the Picture: https://ibb.co/vwDhZPf

The White Circles are connected with HingeConstraints. The Red Circle is my Question. When the Catenary is very up the Pantograph goes up flexible, and when the Catenary is going down slowly the Pantograph is also going down flexible. I dont need any script for that i tried HInge and Rode Contraints that the Pantograph is attached to a uncollided Part 2 m over the Pantograph but thats not that good and i need better ways. Somoene can help me?