Whether the driver are in sync are not the lack of syncopated chuff is not prototypical. I am not sure why people keep alluding to this even if they are in sync on the real thing there will still be a syncopated chuff
I don't think that is true, if by "syncopated chuff" you mean the double chuff that can be heard at low speeds and certain angular mismatches between engines. At several angles the chuff from a simple articulated sounds a lot like a two cylinder locomotive would. It of course depends on the length of the exhaust stacks, so you may actually get double chuffs when both engines match. Remember, there will be four angles, at 90 degrees from each other, that will produce single chuff.
There are no economical ways to simulate this in a scale model except for maybe slightly different gear ratios between engines and sound cams on each engine. You could go to a two motor solution, but most of them involve butchering the boiler and rear cylinder block. Yuk!
