The tiny Hunslet has had a simple change - from the original geared drivetrain to a belt driven one. The lack of a decent supply of tiny gears led to the choice to go to belt drive, even though the engineer in me protested. It's predicatably a bit more 'frictiony' now, but seems to work and is compensated for somewhat by the now lower gear ratio, so it's a bit slower too. 

However, there's still one major issue with this loco. Weight! It's not heavy enough to get consistent pickup yet, so I'll add some lead in the bonnet, and a whitemetal driver. If that's not enough, we'll have to think about replacing the roof with something heavier, and maybe using some of the chassis too. I need to change those pickups for something neater too.