D
Duck
Guest
This video in particular really shows just how crazy amazing it is that the fixed-bogie configuration of these trams actually works! There is no yaw between the bogie and vehicle frame, and the wheels are so close together that they have to "point" the entire first module in the direction of the track at the tangent of the bogie frame. That is a hell of a lot of inertia to overcome for such a close wheelbase!
As a mechanical designer, on paper I never would have thought this would work properly or be an acceptable solution - so it's incredible to me to see it actually working just fine.
I am sure now that the articulation configuration is like this:
Module 1: Bogie frame connected to car body with pitch axis only
Module 1 to Module 2: Yaw hinge only
Module 2 to Module 3: Yaw hinge only, maybe limited roll?
Module 3: Bogie frame connected to car body with pitch axis only
Module 3 to module 4: Yaw, Pitch and Roll hinge
Module 4 to Module 5: Yaw hinge only
Module 5: Bogie frame connected to car body with pitch axis only
This kinematic configuration fully defines each module but permits the required flexibility to navigate any track geometry (within limits). I keep waiting for a rainy day to make up a little SolidWorks animation showing this all.