These classic shots, which were taken at the Peoria Proving Grounds, show a number of prototype models from the days when the company built iron to prove a concept.

First up are a couple of photos of some elevating scrapers that never made it into production, in the shape of 623, 633, and a 653 model.

This series of photos show examples of Caterpillars largest scraper, the famous 657 model. The first two shots show a prototype dual bowl version.

And then two more shots of a tandem version 657, which was basically two scrapers linked together. Once again none of these concept machines went into full production.

And now looking like something out of a Thunderbirds movie, a very futuristic looking prototype scraper known as the Caterpillar 3001.

Finally in this batch, a strange looking piece of kit which was used at the Peoria Proving Ground to simulate” pull” somehow. 

Sadly we do not have much info on this or any of the other photos, but I am sure you will agree it’s very interesting to see shots of unusual items of plant which never made it into production.

We thank John for sharing these rare, and possibly unseen before photos with us here on the Digger Blog.