Hello Daniel, All diesel units purchased prior to 1965 were originally painted black with yellow lettering and safety stripes. These included the first switchers from Alco, EMD, Baldwin, and Fairbanks-Morse, EMD F-Units, GP7's and GP35's, Alco FA's and RS1's, and GE U25B's. My guess is that the GP7's probably wore the black scheme the longest. I have a video of one still in black and yellow at the head of a local along the Eastern Division near Valley Park in the mid-70's. All of them were sold or traded prior to the BN merger. Pat Moreland, Union Mo.
I know the last GP7s were not repainted into orange and white until 1979. I think there were some switchers that lasted nearly that long in black and yellow as well. Paul
I have a photo dated 1979 that shows a VO 1000 in black in 1979 in Springfield Yard (SY). I concur with the black GP7L(s) as late as 1979 as well.
I agree with the GP-7's being in black and yellow the longest. I remember when I was in high school in the 1970's there used to be a black/yellow GP-7 that was kept on the siding in Newburg for switcher duty. George
I don't know exactly how late it was before the last GP35 "torpedo boat" was repainted orange and white, but it was probably sometime between 1970 and 1973.
If I remember correctly, the Diesel Era that featured the Frisco GP35s said that 713 was the last one repainted into orange and white, and that happened sometime during the summer of 1971. Paul
