No if you get Legacy and a Power Master Bridge you can't use your Cab 1's. You could still use your Cab 1's without the PM Bridge but the Cab 2 can't talk to the Power Masters.
Actually Gweedo I think you're wrong and right. The powermaster bridge converts the signal to the Cab1 frequency and sends it to the powermaster. The Cab1 talks directly to the powermaster also. So as long as your just running trains conventionally with the cab1 everything conventional would work (Speed, direction, whistle and bell). You CANNOT have a TMCC command base and the Bridge hooked up together. So you won't be able to control command engines in command mode or any TMCC accessories or switches with the cab1 but all will work with the cab2.
Ron
Anyone know when it will be available to buy? I have been waiting for this. Lionel could not give me an estimated date.
Thanks
Jon Z from Lionel mentioned a June timeframe, but I don't think that's set in stone. 
Yea everything kind of works a little bit of this and and a little bit of that with the bridge. After a while I just set the Cab 1's aside and use the Cab2. The Cab1 comes in handy on the repair bench.
I have the CAB1/TMCC Base on my repair bench as well, it seemed a perfect fit for that use. 
