Lionel makes both O-gauge and HO LionChief sets and locomotives.
Lionel LionChief RTR (Ready to Run) sets come with an 18volt DC power supply that plugs into the LionChief terminal track. To run a conventional transformer simply disconnect the DC transformer and use any Lionel or other hobby transformer that can supply 18volts, AC or DC. Provided the power supply can supply enough ampeage.
When using a conventional Lionel transformer (AC) Or any other hobby transformer (AC or DC) set the voltage to 18volts and leave it. The handheld remote will do the rest. Everything is controlled through the remote, speed, direction, bell, whistle/horn. Many even have other sounds and recorded voice announcements, e.g., "All Aboard" "This is the Polar Express" and more for the Polar Express set. All of this is independent of the power supply.
LionChief RTR sets also come with a battery powered handheld remote that wirelessly transmits signals to the locomotive. The locomotive and remote that come with the set are paired to each other. The remote will only operate the locomotive for that set. Lionel makes universal remotes that can be programed to run other LionChief locomotives, but there are some limitations.
LionChief locomotives were designed this way so that they can operate on any O gauge layout, even Legacy controlled layouts. LionChief and Legacy trains work well together. They both work with 18volts AC. Legacy trains are not designed for DC. Conventional trains must be operated on tracks isolated from LionChief or Legacy trains. You don't want 18volts across a conventional locomotive.
There is much more to this story. LionChief Plus, LionChief Plus 2.0 and more!
I will post more about LionChief trains as time permits.
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