The steam locomotive 99 6001, or ballerina, can be modified relatively easily for the automatic decoupler.
The forerunner and the follower are identical, so the adjustments are identical in the front and rear.
In each case, a small plastic triangle is removed in front of the axle mount.
It is important to keep about 0.5 cm of plastic in front of the axle, otherwise the axle will not find sufficient support.
Here the changes for installation in a steam locomotive DR 99 6001 2x80x
Milled coupling holder
Fully assembled decoupler