Duplo compatible Train

Caution: this thing contains small parts that may break off and become a choking hazard for small children.
The train is based on a train called Lukee which is run by volunteers close to where we live by the Red Cliffs Historical Steam Railway. Pictures of the actual train can be found on their website. If you travel to Mildura Australia this little family friendly railway is worth a visit, just check their website for running times
The aims of this model are to be an approximate model that works on a Duplo compatible platform. Quite a few scale liberties have been taken especially in the undercarriage and firebox (also the real train does not have spoked wheels or buffers). The reasons for this are to make it compatible with Duplo tracks which are significantly wider and have tighter corners than the real train has, and to give the firebox an opening big enough to easily place items in.
Some key problems this model still has are;
There is a small amount of interference with the