Ticket to Toltec , 2nd edition 1992 / Doris Osterwald
Gramps Oil Field, page 88
"During the summer of 1936 the company built the pipeline to Chama. In 1937 Hughes also built his own refinery in Alamosa."
"The March 25, 1937 Alamosa Daily Courier reported:
The transfer depot, which is being built near the railroad shops, will accommodate twelve standard gauge cars and two narrow gauge cars. Eighteen men are employed in building of the station.
Tracks for the cars and pipes for the transfer of the oil are being installed. An elevated track is being constructed for the narrow gauge cars and a depressed track for the standard gauge cars so that the oil may be transferred by gravity."
The Osterwald book also cites the Chama Valley Tattler, Summer 1994 Volume 12 (written and compiled by Margaret Palmer).
Gramps Oil Field, Page 5.
"The first productive oil well on the Hughes ranch was drilled in 1936. ... Very soon after striking oil, they began working on fifteen miles of pipeline to carry the oil to Chama where it was pumped into oil tanker cars to be carried by rail to the refinery. ... The pipeline took one summer to lay...."
Page 6 of the publication includes the image Dave Grandt posted with a caption that says 1936.
Page 12 includes an excerpt from The Gas Journal March 26, 1936 that described a 3-inch stream of oil flowing from No. 5 Gramps in the Price district of the Archuleta County in the Dakota.
Certainly not definitive but likely narrows the date range putting it into 1936.
Dave Adams