I have acquired a Williams Scale GG1 recently, used. I opened it up to replace the lamps and noticed that there is a Lionel circuit board inside. The previous owner installed it as I don't believe it was there when the loco was new. There is a 9 volt battery connector but no battery. The sound operates well. It has the usual sounds of a GG1 plus horn and bell. So why is the system operating without a battery. Should I put one in ? Should I put in a BCR ?