Electric Marble Lifter - Compatible to Gravitrax (R) V0.9

This is my first try to create a marble lift.

It uses a spiral drive mechanism to lift up the marbles.
The lift has 2 entries with 2 corresponding exits and 2 marbles can be lifted at the same time. With every rotation of the spiral, it can pick up marbles.

There is short video showing the basic function: https://youtu.be/G2JuTBZbeCU

The spiral is a bit a special design, as the profile changes along the way up.
In the bottom the profile is concave, in order to pick up the marble e