This may be a one of a kind photograph of the 2nd Engineer motorcycle orderlies at Engers, Germany. This scan is of a photographic print. It does not come from a postcard. (Harley-Davidson Motorcycles)
There is a second photograph of the 2nd Engineers with  two motorcycles titled: Motor Transportation and R. S. O. 2nd Engineers # 324 If anyone should happen to own a copy of it, I'd be very grateful to have contact from you about it. My grandfather is in the photograph. I would very much like to have a copy!