I just recently found the below website, and found it very interesting that they didn't know what the small building on the railroad property was for. On the website's map it is identified as "5LA9425 Associated RR Structure"
Here are the website's photos of "5LA9425 Associated RR Structure". It is the small building on your right as you get on I-25 going north at the N. Commercial entrance.
I won't hold everyone in suspense this time. :D
Many Trinidad residents have probably noticed this building from time to time. This building was the Santa Fe RR's Water Treatment Plant for the water used in the steam engines up until the mid-50's. The chemicals were mixed with the incoming water and then pumped into the old cylindrical water tower that was along side of this building. The water was treated to prevent the water from foaming inside the locomotive's boiler. Most steam locomotives that were used as helpers on Raton Pass filled up at Starkville on their return to Trinidad, because the water was free, and Starkville's water didn't need treatment like Trinidad's water did.
Link to Colorado DOT's website map of historical buildings.
There is a lot of additional information on historic buildings, and structures on the Colorado DOT's website. Some of these buildings have been discussed previously on the forum.
I hope some find the above informtation, and the website interesting. :) [8D]