Ugh! Rejected again by Shapeways!
This is getting to be a bad habit!
Anyways, on the ends of the 4000's, I had a bracket to hold the destination sign. Apparently 1/2" thickness in O scale is too small due to "thin wires".
The pictures from Shapeways:
So, no built in brackets allowed. I've left a small, square pad where I can attach the cross piece to hold the destination sign.
This error is unlike my first error. That first one was just sloppiness on my part. I didn't properly size part of a model.
On this error, I guess I just pushed the boundaries of the material too far. Oh well, corrections have been made (again).