SD40 No. 746 is from the second SD40 order of four units (746-749) delivered in March, 1970. These four locomotives were identical in appearance to the first ten delivered the previous year. All of the Soo's original SD40s were delivered in the 1962 red and white scheme illustrated here. The unique electronic bell, extra cab windows, rerail frogs, and footboards were also common to the three SD40 orders

SD40-2 No. 777 illustrates the "parallelogram" scheme as it first appeared on units 775-786 delivered in October, 1974. The end of the long hood was left white, and the "SOO LINE" lettering was removed from the nose. In addition, the road number was removed from the cab and placed near the walkway towards the end of the long hood, where they eventually proved difficult to read. SD40-2s 757-789 were delivered with many of the same features found on the earlier SD40 orders, such as the extra cab windows, footboards, and small 3200-gallon fuel tanks.

SD40-2 6612 was built in 1980 and delivered in a compromise between the 1974 scheme and the previous scheme, one dubbed the "hockey stick" paint scheme.

SD40-2 No. 6623 was the last domestic SD40-2. Constructed in August, 1984 as part of an order for six units (6618-6623), it featured the latest design improvements to EMD's long SD40-2 production run, such as the distinctive free-flow "laundry chute" blower duct located behind the cab. By the time these six units were delivered, the standard location for the air horn was next to the strobe atop the cab roof. The black appearance of the walkways was due to the application of an anti-slip paint. This black coating eventually wore off over time, exposing the white paint underneath.

SD40 No. 750 was delivered as part of the Soo's third and final SD40 order in May, 1971. It's electronic bell and footboards were removed, and the extra cab windows were plated over sometime during the late-1970s to early-1980s. During the mid-1980s, the unit received a larger plow and its horn was moved to a location adjacent to the strobe on the cab roof. This unit received ditch lights, and its horn was moved back to the long hood around the time it was repainted into candy apple red in August, 1991.

SD40-2 No. 6607 was the first Soo Line locomotive to receive the unified dual flags paint scheme, having been repainted in April, 1993 at Shoreham. Like the other Soo SD40s/SD40-2s still in service today, its horn has been moved back and ditch lights now rest on the front porch. This unit received a dynamic brake retrofit in April, 1990. Note the unusual bulge in the dynamic brake blister: this is a feature common to all units retrofitted with dynamic braking.

SD40B No. 6450 was quickly repainted into the "hockey stick" paint scheme before it entered service on the Soo in 1987. The dynamic brake housing was moved to the front of the hood from its usual location when it was rebuilt by the Burlington Northern in 1981 after a wreck. During the early 1990s, this unit received the "Proud To Be Part Of CP Rail System" decal under the road number on the hood -the only SD40 to receive this application.