Duplo compatible curved train track rails with internal printing support structure for easy printing without additional supporting materials. The piece is similar to and compatible with the original part (30 degree segment, 26 cm radius of curvature).
The 20130712 stl file has two parts in a single print without version number markings (as seen in some of the pictures).
The 20131127 files have an increased width of the vertical rail part for greater strength (requested by Smuk3D). The additional width can be adjusted in the scad file (parameter in first line).