Then in that case, I would rather have open section sleepers.My apologies, you are correct about the seating capacity of the Railbed cars.
The economy (coach) cars on this train only hold 51 seats, as compared to a V-2 that holds 60 seats. I suspect that the cars are smaller than Amtrak cars, as the Queensland service is 3'6" narrow gauge. Thus, a V-2 sleeper shell would fit more than 19 Railbed seats. The problem with 2-bed private rooms is that beds are taken out of sale if you don't have enough couples to fill the rooms. Open-plan lie-flat seating allows the operator to keep every bed available for sale right up until departure.