Grand Trunk Western SD40

[ShaunCN]

Dose anyone know when the GTW started painting their SD40 locomotives in the blue and orange scheme like this one: http://www.rrpicturearchives.net/showPicture.aspx?id=17593

the blue scheme replaced the originall black one like this: http://www.rrpicturearchives.net/showPicture.aspx?id=17594

the GTW units were bought in 1969 and 70 if i remeber correctly.
just unshure of when most units got the new(er) blue paint
thanks for any one's help [8D]

[CShaveRR]

I'd say the early-to-middle 1970s is likely. GTW got its GP38ACs in about 1971 (low 5800 series), and those were delivered in blue.