To start with, I'm a DCC rookie.  I recently purchased a new Bachmann RF-16 with DCC w/o sound, factory equipped.  I now need to add sound, but there may be a problem.  I've had to add several lead weights to the chassis and to the inside, top of the shell, just so it could get traction and actually move down the tracks.  Consequently, the sound module is going to have to be extremely small.
        Also, I plan to obtain the 'B' unit in the near future, (also powered) and if it requires the same amount of weight to get traction, then the space problem will remain.  Am I in deep doo-doo here, or is there less of a problem than I am anticipating?  Needless to say, I am in desperate need of some expert advice.  All assistance will be greatly appreciated.
                                                                                                                                Thanks, Bob