Here is the version I heard from ther late Ben Greathouse. Redington was one of three Irish friends thast hired on in 1898. He was not a well man, and like a lot of old railraoders, he hid his infirmity and remains a mystery. Though he had been living in Chama, he transferred to the Chili Line bacause he had trouble throwing over the cutoff ("Johnson Bar")on the newer K-class engines.
Apparently the runaway started not long after the train left Barranca and began the descent to Embudo. According to train crew and John Delgado (USPS employee), they saw both men struggling with something on the engineer's side. The fireman may have been trying to pull Reddington out of the seat. The #174 derailed on the approach of a large curved trestle, and slid across the trestle on its side before flipping upside down on the south end. The three car train went into the arroyo and were so damaged they were burned on the spot. The enginemen were retrieved in pieces. Reddington's torso had third-degree steam burns in the crotch area, so the speculation was that the injector pipe broke, and his attention went from braking to his burns. He was in poor physical shape and could not jump away from the seat.
Alamosa railroaders were considered some of the best on the D&RGW system. Retainers? As long as Conductor Hines turned up the retainers, he did what he was supposed to do. Passenger cars should operate ONLY in the 10-pound position. The 20-pound position (or slow direct) is only for freight cars that are loaded at or near capacity. Otherwise the wheels would lock up and slide.
The FRA still has the ICC report on this and other accidents on file, and it can be downloaded, I believe. ICC reports are clearly written and fascinating, and often display excellent detective work.