If you want to try out DCC and don't want it to have any effect on your current 3rail AC layout, here's an approach.
Upgrade one of your locos with a BlueRailDCC (available from Tam Valley Depot) coupled with a Tsunami DCC decoder. The BRDCC will operate on AC without any mods to your layout power and the Tsunami decoder will provide full access to DCC.
Download the free Blunami app onto a smart device. The app is compatible with the the BRDCC, will provide full access to all aspects of DCC and includes a simplified approach to CV settings. This avoids the expense of a DCC controller.
You will be able to check out DCC with no impact on your 3rail AC layout.