The GP40TC locomotives was the first engine GO Transit bought. Purchased in 1967, featuring a 16 cylinder 645E 3000hp engine, no dynamic brakes, and a separate 500hp engine to power the HEP generator. They were esentially GP40’s mounted on a longer SD40 frame redesigned to house an additional HEP generator and motor. Eight locomotives , 600-607 made up the initial order. Initially, they were delivered in blue with red handrails and sub lettered CN where they tested primarily in freight service. They received the white cab, white front pilot letterboard and the GO Transit logo when they began service on GO transit.