Here I have enlarged my 08 shunter to Gauge 3, 2.5-inch gauge.  I did this some time ago, now final finishing a few things and tidying up the files. 

To save space I've added zip file.

Peter D.  August 5, 2024

 

Update July 17, 2025.

As for the motor and gear boxes, let me suggest 600 rpm as a better choice.  The 300 rpm will give a top scale speed of 20 mph.  The 600rpm should do this at half throttle and allow for battery decay and loads.

Peter D