Only one little problem. It never happened. That pix was taken on an outing to Embudo I believe. The Manhattan Project never used the Chile Line for transportation. Most everything was brought up to "the Hill" by truck from Santa Fe and beyond.
Passengers traveling by train to the Project were met in Lamy and went from there by car. Very commonly they would lay over in Santa Fe before going on to Los Alamos.
There is a wonderful book on that era entitled "104 East Palace", written basically about Dorothy McKibben, who ran the office at that location. Every official visitor to and from the Hill had to pass through this office. Officially, Los Alamos didn't exist at that time. There were, and probably still are a few people around who have 104 East Palace. Santa Fe, as their birthplace.
Fascinating history. Regretably there is no plaque or such at that location to commemerate its importance of that location.
The author of the book is the daughter of (Sir) Dr. Arthur Compton, who went on to be the Chancellor of the Univ. of California.
CJ