I believe the LionChief engines without cruise and volume control and automatic couplers will remain the default engine for entry level ready to run sets. The LionChief Plus engines will continue to be premium mid price range engines with the added features. I haven't heard anything to the contrary.
Just to clarify both product lines run on AC or DC power.
That said not all the LionChief engines in the rtr sets are equal and you may notice it reflected in the price. I've noticed the Polar Express seems to have more torque and positive drive than the Silver Bell Express. The Silver Bell Express will free wheel on a decline, where as the Polar Express though without cruise control and still has minor free wheeling charactoristics can be controlled on a down hill run with voltage drops.
I'd like to know if anyone has experience with the LionChief Broadway Limited rtr set and could comment on its performance.