A friend of mine, who is a long-time railfan, sent me these pics of some SP diesel power in the 1970's and 80's. He chased the trains and took the pics.
1.Cotton Belt SW1500 2515 is at Forth worth Texas in September of 1982.
2.SP MP15 #2752 idles at Fort Worth, TX, September 1982.
3.SP renumbered GP9 #2875 on the whiskers at the Bayshore Yard in Brisbane, CA. This is January 1979. Note #1329 near the side of the roundhouse.
4.SP SDP45 #3200 is in West Oakland, CA, in April of 1979.
Matt