There are some photos of log cars in the portion of the Walt Ainsworth NP Locations collection at the NPRHA website.  It is a little difficult to find the link, and more difficult to filter, but here is a link

http://www.nprha.org/Lists/WWANL/AllItems.aspx

An example - once in the web page, you can scroll down 5 pictures to find a 1953 log train on the Auburn wye. 

Searching the site is awkward - we are working on better software.  But once on Walt's Location page, click on the right site of subject 2 to get a menu.  Scroll down and check "log train" to get access to 17 pictures that meet that heading.  You can do the same on subject 1, but there are only 2 pictures.  You can also check "car-lot" but there is only one pic currently posted.

We are working to put up more pictures that have been scanned and indexed.  That's not in my shop, so I don't know how soon it will happen.

Unfortunately, you can't get more than the thumbnail from web site.  But you can contact Pacific NW Railroad Archive for a better print.  info@...

Hope this helps.
Chuck Soule