Ok so lets look at the evidence. Linn made a good point about RWR saying that he
heard that the C&S turned the tires but the pictures don't show this.
The pictures that Kelly posted show no half flanges in 1941 but shows them in 1948. There is also a shot of 346 in 1946
with the half flanges. And there is several more pics in the book that Dirk did from 1940 and 41 without the half flanges. 346 didn't go to the MLC till 1947. So that rules out the Lumber CO turning them. SO that only leaves the RGS, or the Grande.
As I posted before from Dirks book 346 was on the RGS in 1944 to the summer of 45. The RGS stated in 44 that the running gear was in need of repair, including driver box lateral. As I also stated earlyer, the RGS may have considered turning half flanges cheaper than buying the material to properly fix the lateral problems.
In the summer of 45 346 was sent to Alamosa for repairs, Dirk lists in the book that the tires were turned. The Grande may have also considered it cheaper to turn the tires with half flanges. As some of you have stated the Grande was not spending a lot of money on the C-class loco's anymore.
So after reviewing the evidence my money is on the RGS or the Grande turning the half flanges.
I know that RWR said the C&S did it, and it makes a great story and all but the pictures and other evidence says other wise.
Also wasn't 340 last shopped in 1949? If so then she might have been the last c-class to be shopped.