This features an adapter to house a CD motor for Ringfield motored Hornby and Lima locomotives. this will help to improve performance as the CD motors have much better slow speed performence, they are smoother runners and will draw less current. It also includes replacement gears which will reduce the noise produced by the mechanism. The adapter can be printed in resin or by FDM. The gears should be printed in Resin  as it needs to be very accurate using a tough resin like Sunlu Nylon like or Formlabs as it will be under significant stress and will need to be durable.