RSD's

[rlandry6]

I know the Alco RS locos were introdeced in the 40's What about the RSD's? Visually, they look like RS's with 6 axles. Would they be out of place on a 50's layout? Were they longer than the RS's?

[AltonFan]

Most of the RSD and RSC units were sold at the same time as their B-B bretheren.

[dehusman]

Short answer. No, they would not be out of place.

Dave H.

[brazos87]

RSC's had an unpowered middle axle on each truck--used to distribute weight on light rail. RSD's had all six axles equipped with traction motors.

[CSSHEGEWISCH]

RSC2/3's would fit in your era and would be most appropriate on a weedy, light rail farm branch that sees very little traffic outside of the harvest rush.
RSD4/5's are a bit heavier but would still fit on a light rail branch (C&NW in South Dakota) or in mine run service.