Rick's response above is correct and very doable. You can also invest in the DCS system and hook it up next to your Legacy system, the two work very well independently on the same track. Legacy cannot operate a DCS locomotive probably because MTH would not release their technology like Lionel did 20+ years ago. If for some reason you would want to operate your Legacy locomotives with the DCS remote, their is a DCS/Legacy cable available from MTH which makes that possible. It was great when Lionel only had the TMCC system as MTH designed their DCS system to fully access the TMCC system. However, Lionel changed their game a bit and offered us a TMCC on steroids known as Legacy. The DCS remote cannot access many Legacy features such as the quillable whistle but it can access many other features. MTH would have had to redesign their remote with a button similar to Lionel's sprung loaded lever. They do have a quillable whistle also but it is more cumbersome to operate and cannot access Lionel's. I hope this is helpful.
-Ralph
