took a nice design and modified for my needs.designed motor mounts to house the common china 16mm gear motors available from 50-300 rpm.ive used the 150 rpm and found it was plenty power and scale speed.
motor mount are a cap design that squeezes the motor into place.
modded the hub to allow the planetary gearset to be recessed inside the hub and accept a common 3mm d shaped shaft.
the motor stand slides into the stock bruder frame,its designed if tracks ever stretch you can raise the entire motor section and ad a shim to increase tension on both motors evenly.
on the drive drive hub after printed clip off the small standoffs between the cogs.....this a great design in stock form.

i printed petg 100% infill