After you have purchased the Power Cab you may find that wireless is something you want. If that is the case the question becomes: What will be running the trains.
The two cab option: The Power Cab MUST remain plugged in at all times to run the layout and supply DCC power to the track.
5240023 RB02 Wireless Base Station 916.50 MHz
5240011 Pro Cab-R . This is a Pro Cab with radio installed
5240040 CAB06r CAB06 with radio installed
If you want the Power Cab itself to be wireless you must also purchase the SB5 Smartbooster to put DCC power on the track so the Power Cab can be unplugged.