Im so sorry! I know this is a pretty old thread now but time was wild and i couldnt get to work on this. So after all these months i finally was able to fix it using a cog with a 2.5mm hole instead of a 2mm one. I also used your guide Super (more or less) and got it on the axle without damaging it and it sits pretty tight aswell. Now the Locomotive runs very nicely and im glad it does! Thanks to everyone
Cheers Ron
Cheers Ron