Historical note: Warren E. Fenzi, President of Phelps Dodge (1975-1980), in an interview (book length), discussing the railroads used by mining companies in south-eastern Arizona, said, "the amount of railroads in that part of the world was unbelievable. Small guage, most of them, but not all of them."

"Junior Engineer to President, Director of Phelps Dodge, 1937 to 1983" —interview conducted by Eleanor Swent in 1995, Regional Oral History Office, Bancroft Library, University of California, Berkeley - found on the internet for free download.