Re: Rio Grande/D&S change-0ver

I wasted a bunch of time searching for the original films, and did not find them, except I did find the mini-dv tape that had the film to video transfers on them. There are two 400 foot reels on the one tape, thus about 40-45 minutes. The tape says Nickel Plate 765 tape 1 and 2. These were films I used in a 2015 video "Nickel Plate 765-The Early Years". Its all sound. The 476 shot in the clip is the very first clip on this reel. The very next shot is December 1st, 1979, on the very first run of 765 from Fort Wayne to Bellevue. So, if this clip was really shot on that reel of film, it has to be between 1977 and 1979. I was in Chama/Durango in 1976 for sure(silent film camera), and I believe the first shots of sound I did were in the spring of 1978. We know the D&S had their trains relettered for the 81 season so while I have it narrowed down, its driving me crazy I cannot figure out exactly when I shot it. As far as I know there are no other films of this train or that time period. All the other reels that I remember were 1981? I need to find the reels of that trip next!!!
By the way when I played the tape, the camera I used while playing the clip had far more audio dropouts than the clip I had here. There was one audio dropout in the clip above. I used a cleaner tape before I put it away. Soooo, it means I should preserve this clip for future use, as it might be the best one. If anyone has a way to pinpoint when this might have been shot, let me know. Was 476 in service in the 1977-80 time-frame entirely???
Greg