The ball lifter now has a track to go with it:
The track screws onto the ball lifter mechanism frame. It can all be disassembled if maintenance is needed on the mechanism. A little oil is all that the mechanism might ever need, but building this as a solid unmaintainable structure would be the wrong way to do things.
I took a few photos while I was finishing the track. They show the unfinished track, and make some of the parts a bit more clear.
Close-up Track to Frame Transition
The track to frame transition look crooked, but because the turn is banked, the ball moves smoothly from the track to the frame rails. Actually, the glass marbles are not as smooth as the steel ball bearings or the polyethylene balls because they are smaller. But the tiny bump is not noticeable to the marble or to the viewer.
Track to Frame Attachment Points
In some cases, the attachment points for the track are also the connection points for the frame rails. On the left side of the image above, you can see that the track is connected with a screw that is also holding the frame together. In the middle of the image, the frame is tapped (threaded), and the screw is only used to hold the track in place.