This is excellent! Always,perfect!

They are custom LEGO compatible drivers made by Ben Fleskes at http://bigbenbricks.com/ I needed smaller wheels than what LEGO makes to match the prototype C-16 well enough.

No I mean the lego wheels, those are not avrige size.

Carter, steam locomotives have different sized drivers to match their type of use, passenger locomotives use large diameter drivers for high speeds whereas freight locomotives, such as the C-16, used small diameter drivers and more of them for better traction and maximum torque to haul heavy loads.

why are the driving wheeles so small?

Trains don't appear to be very popular around here, but don't let that dishearten you. I think you've done an awesome job with this locomotive. Beautiful work!

Thanks mate. :)

Very good work. As always;-)