A modest proposal ...
Consider buying a Lionel CAB-1L (instead of a CAB-1). A CAB-1L builds-in several LEGACY features, so it can "talk" to some of the features of LEGACY-equipped locos. However, a CAB-1 device will also "talk" to a Legacy-equipped loco, but it can address only the most-commonly-used features.
The add'l cost of a CAB-IL is worth it for use on a layout that is oriented to TMCC/Legacy by intention.
A CAB-2 is another option and a big leap forward. It's pricey, but it will "talk" to every LEGACY feature -- including ones you may never need or use. High-tech operators can't seem to get enough of that technology, and Lionel keeps extending the boundaries of the system.
Perhaps the next level of emerging technology will be a brain wave sensor hat that converts your dreams about model trains through a neural network into commands that run your railroad neurologically while you sleep - with dream-based feedback so you can '"see" and enjoy the ride.
Mike Mottler LCCA 12394