What a wonderful photograph. And yes, imagine trying to be a brakeman on the running boards trying to leap from car to car given those height variations - while the train is moving and the cars are rocking.
The interesting load might be threshing machines but in staring at it, it could even be two steam fire engines of the era.
As for that very large boxcar at the end of the train marked "woodenware," the car itself looks to me like one of the many Menasha Woodenware boxcars (although the lettering scheme is different) that were featured in the November 1940 Model Railroader page 618-619 (the page numbers continued from issue to issue back then) and reprinted in the Model Railroader Cyclopedia for 1944. Car length was 51'3" which was huge for that era. Built between 1890 and 1908, the cars remained in service until 1935. One source suggests some of the big Woodenware boxcars were refurbished circus boxcars.
I have a recollection that a craftsman kit of that car was available in HO many years back. At one time one of the prototype cars was in the collection of the railroad museum in Green Bay WI.
Magnuson even offered a model of the Menasha Woodenware structure. They were a big company. One of the boxcars shows up here
http://menashabook.blogspot.com/2013/09/wooden-ware-back-view.html
When the Chicago & North Western Historical Society met in Des Moines some years back, we were privileged to ride in the Union Pacific's business train over the Kate Shelley bridge, then got off the train and were permitted to walk on the replacement Union Pacific bridge next to it, which was still under construction. Then the UP business train (headed by the remaining C&NW painted units) did a photo runby for us. And then we got back on the train, got off at Boone, and ate a catered lunch on tables that were set up in the yard itself - an active yard and there we are eating sub sandwiches in the middle of it. And the next day we had a long ride on the Iowa Interstate on former Rock Island trackage.
Dave Nelson
The flat ahead of the stock car probably has threshers on it:
https://en.wikipedia.org/wiki/Threshing_machine
Also note the variation in car height.
Dave H. Painted side goes up. My website : wnbranch.com
Another fascinating photo from Shorpy!
http://www.shorpy.com/node/21370?size=_original#caption
Great construction details, footers. What do you suppose the flat car load is just ahead of the stock car? Possibly fire engines? looks like a pumper's surge tank in the profile.
There's a brakeman standing on the roof about five cars from the head-end and another interesting flat car load. I'd love to see a color photo of the last car something, Woodenware...
This must be the Kate Shelly High Bridge in Boone, Iowa.
https://en.wikipedia.org/wiki/Kate_Shelley_High_Bridge
More neat photos here, including the U-P's replacement bridge:
http://ogrforum.ogaugerr.com/printer-friendly-topic/my-favorite-railroad-bridge?forReply=33950814971463136
[edited to remove the amp;&&amp from the title] &
Have Fun,
Ed