My website had quite a large number of links to photos and drawings from the John Maxwell Collection, which for a long time was available for purchase from colong.com. But the site was run by John's son (I believe) Bruce, who recently passed away.
The website is gone now, and I don't know of whether these fine resources are available any longer. I just finished updating my pages to remove all those links. In many cases, his were the only photo references I had.
It's sad, because a lot of manufacturers, as well as modelers and historians, depended on this material for their research. Perhaps whoever inhertied the estate will donate or sell them to someone who can continue to make them available.