This design is for a Hornby/lima model with a bo-bo wheel arrangement using a CD-ROM motor to replace the existing Ringfield motor.

These designs are for a CD-Rom motor that is 24mm in diameter and has a depth of 12.5mm, various holes have been added to the design to accommodate pre or non-wired motors. I have also added a cable management loop to feed cables through. You will also likely need to buy a drive gear to attach to the shaft of the motor, you may need to trim 1-1.5mm of the end of this gear. On my Lima class 33 I used 8 Tooth 4.8mm / 2mm Drive Gear - https://amzn.to/3T0DNmF (Amazon)but for the Lima/Hornby Class 43 I used a 6mm diameter gear with a 2mm internal hole.

Note 1: CD-Rom motors come in different sizes and the most common is a motor with an external diameter of approx. 24m and a depth of about 12.5mm (motors with a depth of 12.5mm can't be used on models with a co-co wheel arrangement. The shaft of the motor needs to be 2mm in diameter and about 5-6mm long. Note 2: If the housing of the motor is made of metal you will need to insulate between the housing and the motor, this can easily be done with some sticky plastic or a spacer on the edge of the motor that comes in contact with the housing. Personally I enlarged the hole to 8mm so the motor sat better in the housing with some sticky plastic to insulate, alternately I have included a spacer to do this job.Note 3: For Motors that are less than 12v rating, then it might be worth researching installing diodes between the DCC decoder or track pickups and the motor to reduce voltage getting to the motor and limit the chance of burning out the motor.

I have also created a separate design for a co-co wheel arrangement using a CD-Rom motor that has a depth of only 9mm, this can also be used with bo-bo wheel types (9mm deep motors are harder to get hold of but can be bought a aliexpress.com).This model has been designed to be printed on a resin 3d printer. The example in the photos has been printed on an AnyCubic Photon 3D printer and used on an old Lima Class 33 loco.

I use AnyCubic Water Washable Resin for most of my items but use AnyCubic ABS Like Resin for anything that needs to be stronger and tougher.

use this link to join CGTrader and download my designs.

https://www.cgtrader.com/designers/PJD1974?referral_id=3218445