Optimized looping with slope - Gravitrax compatible

This is an optimized loop, whose entry has been adapted to the incline of the track.
It is therefore possible to send a ball through the loop with a standard rail and 4.5cm or 5cm height stones.
If the ball arrives with a bit of momentum, 4.5cm of height stones are sufficient, with 5cm height stones the ball does not need great initial speed.

A model to print could be found under:
https://www.printables.com/de/model/354877-optimized-looping-with-slope-gravitrax-compatible

or

https://www.thingiverse.com/thing:5751905