Use of hydraulic elements for the draft gear

The use of hydraulic elements for a draft gear make it possible, to realize any characteristic for springing and damping according practical demands.

But a principle disadvantage remains: In any case at one element is to seal the inner room against the 'outside world' at a movable part - mostly a piston - against leakage of the fluid inside. There was no solution for this problem in this time - especially for a long lifespan.