T-12 operation between Alamosa and Durango?

In attempting to use the tonnage rating charts in employee time tables to approximately establish when certain classes of locomotives would have operated through Chama, I was struck by the fact that the Rio Grande employee time tables covering the 4th division (or other name at the time) do not include T-12 or class 47 engines in the tonnage rating tables. However, the Alamosa ETT No 114 of June 17, 1928 does include T-12 tonnage ratings for RGS trackage only, and the Third Division ETT No 100 of March 28, 1920 does include Class 47 in the tonnage rating charts. Copies of the 15 EETs available to me were dated from 1912 to 1951.

Was the operation of T-12's on the 4th division something planned in detail out of the chief dispatchers office so the crews did not need to figure tonnage along the route?

I would appreciate information or thoughts on how tonnage was accounted for on passenger trains pulled by class 47 or T-12 engines between Alamosa and Durango, and especially how it was accounted for on the Santa Fe branch given for part of the times those engines would be working with variable tonnage as freight cars were picked up or set out long the line.

Thanks,
Dave Adams