That's a normal old time log loader. It can straddle flat cars, look at the 'hump' built under it. Also, note that some of those logs may have been loaded from the side. It appears that it is set up for a cross haul too.
Looking at that picture again, I think that the timbers I thought may be used as a cross haul are just there to make the logs slide easier and not snag on the car. The sheave at the top of the boom is free to swing, and the machine is heavy. So, they just need to move the logs up beside the car, grab them and guide them into place with the tag lines. There is a picture of an overturned loader on the net, must have tied onto too big of a log!
Playing with Google reverse image search found this,
"15 historic photographs by Russell Lee of Lumberjacks in Minnesota.
Minnesota’s history is synonymous with logging. In 1937, Russell lee traveled to lumber camps in rural Minnesota.... The following images were taken by Lee when he was employed by the Farm Security Administration." http://www.photistoric.com/historic-vintage-photographs/minnesota-loggers/
That pic is down the page as link to a 1429x2000 hi res image.
Last edited on Fri Mar 18th, 2016 12:42 am by Kitbash0n30
____________________ See y'all later, Forrest. Screw the rivets, I'm building for atmosphere
The McGiffert loader was self-powered. Hard to see in those photos...the powered wheels were chain driven and folded up under the frame, just below the "deck". Loaded log flats were pushed in front of the machine and it would unload the logs and then the empty was pushed underneath and the next loaded car was unloaded...and so on. When it came time to move on, the driven wheels were lowered onto the track and the McGiffert rolled on down the line. It was a sight to behold, there are a few in museums across the US, a couple here in Texas and Louisiana. I built a model of one in On30 gauge years ago...wish I still had it. It wasn't powered but looked cool sitting in place above the cars.