To fix the wheel in it's new position I needed a method to hold the wheel axle in position. One side is just a hole in the PCB (tehre are large areas only ossupied by the ground layer, so no harm, if a little hole is missing (position was marked before):

The other side is fixed by using the original decoder part, which I fixed in position with 1mm copper wire (silver coated). soldered in the previous holes of the ground pins and in new holes I drilled into the ground layer (and removed some of the coating):

Contacts are bridged with some wires. A short test proved everything electrically functinal.