In the Bachmann train set, stock # 00501, the description states it is DCC and controls light, speed and direction. Is it possible to add sound or any other DCC controlled functions? Also, if it is possible how expensive and involved would it be?

I am new to model railroading and I am trying to learn as much as possible before buying my first set. At present I plan to go with DCC at the very beginning. I also intend start fairly small and grow my railroad using the rockies as the setting.