LED HEADLIGHT???

The RailSounds Commander is the complete sound package, all you need is the serial data from a TMCC receiver to trigger the sounds.  You can use the RailSounds Commander with the ERR TMCC products that provide a serial output (virtually all the TMCC "Commander" products).

You could use it with a standard Lionel TMCC package if you tap off the serial output, but that's probably not used that often.  Most Lionel packages provide for the plug-in of the standard RailSounds audio and power supply boards.

Gotcha John, I think I already knew that the kit came with both boards, just didn't say it.

But, if I want to keep the cruise capability, I'll need to keep the CC board in place, correct?  Is there any redundancy in keeping the 2 kits (Cruise Commander and Railsounds Commander)?  ERR lists the Railsounds Commander for $100.

You can buy both of the kits for a discount from BoxCar Bill on the forum here.  He also offers a package deal of the Cruise Commander and RailSounds Commander for $185 last time I bought one.

There is no redundancy between the two products, they work hand in hand, but there's no overlap.  Yes, you need the CC board if you want the locomotive to move in any fashion.