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.
5240023 RB02 Wireless Base Station 916.50 MHz $159.95
5240011 ProCab-R ProCab with radio installed $249.95
5240040 CAB06r CAB06 with radio installed $189.95
If you want the Power Cab itself to be wireless you must also purchase the SB5 Smartbooster
to run the layout and power the track so the Power Cab can be unplugged.