Hi Basti, thanks for the file.

Typically, the flip 180º is upside down-wise. Hence, the file clears that up.
This is a good example of why I typically ask for a file. It communicates better. Whether the file that is sent back works or not, we have a base to move on quickly.

Please have a look at the three files below.

The first one (…01.c4d) uses the Spline as is and introduces a Null to take the rotation correction.
The Null is useful anyway. If the model needs to be swapped out, it's less trouble, and it's even better to have more Nulls.
CV4_2024_drs_24_ANfl_01.c4d
The problem with this setup is that it will render Motion Blur incorrectly, as it has some 180º "flips", which motion blurs a lot.

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The second file (…11.c4d) uses the Spline. There are three copies, each just the part needed. Segment 0 is untouched. Segments 1 and 2 are Spline> Point Order> Sequence Reversed. Then, Object Manager> Object> Connect.
The Align to Spline Tag has an option to use Segments.
CV4_2024_drs_24_ANfl_11.c4d
The advantage here is that the setup is faster if a Rail spline is needed.

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The third file (…21.c4d) uses the three Segments as separate objects, animating the Spline Path field instead of the Segment Field.
CV4_2024_drs_24_ANfl_21.c4d
I hope you will find one suggestion that fits your style of animating.

Let me know if you have any questions. I'm happy to look into it.

My best wishes for your project