In certain circumstances, a car needs to be unloaded from a specific side. That's when the B End is important. But it may or may not be to the rear.
A hopper that is being unloaded by rotation requires the B End to be in a specific direction (to the rear) but that is about it.
KCS 4612, an AC4400CW, at 32nd Street Westbound. Unfortunately, the second, third and fourth units would also have made good photos, but they train was moving too fast.
These and many more photos can be found on http://madisonrails.railfan.net
I believe that you are basically correct in thinking that the wooden/metal elevator was still very much in use in the 1950s.
Concrete was used on very large elevators but the majority still was the wooden type.
Go for it!
I use Railfan.Net http://www.railfan.net/ for both my Railroads of Madison County and the CID, NMRA division websites. It cost about $80 per year (per site). I pay for mine and the CID pays for theirs. We have been there several years, and have been very satisfied with Railfan.Net. They call...