T-12's, K-28's & a bit of chili

OK, now that I've scanned thru *most* of the archives I can start asking my silly questions.
I've often read/heard that the T-12's were used on the chili line until about '33 or '34 because of light rail which was replaced about then, allowing the mixed to switch over to using K-28's. Here's my question: In the 1938 Branch Line report reprinted by the CRRM there is, on p. 267, a listing of rail laid on the Santa Fe branch. This list, which dates from '38, shows no replacement later than '28. So, assuming that this list is wrong, where was the replacement made which allowed the change in power? Or was it some other change (bridge work, cut-widening, or something like that) which allowed the Grande to start using K-28's on the Chili Line?
Or perhaps they just woke up one day, smacked themselves on the forehead and said "Wow! We could've been using K-28's!"
hank