I found a neat animation or simulation of this model on YouTube.

Here is a link to see the video.

I did a concept layout in Sketchup using the gear pitch diameters, to see if the over-all model size would be ok.

I decided this was too big of a model, so I scaled it down some......

I am going to use the new version of the GearDXF program on my computer to make the gears.

The standard scaling factor was .083333 on the spur gears, so I used that ratio to scale the rack gear and it seemed to work, by checking the fit of the rack teeth to the gear teeth.