Welcome to BPT Clicker
You are correct in using Distilled water and as Mr Ripley says the Minerals in tap water can collect and damage the the train. In fact I use distilled water in everything like coffee makers humidifiers, trains etc because of mineral deposits that can shorten the life of any appliance. One should always have at least a gallon on hand for such things at its really not that expensive, at least not in my neck of the woods.
You are correct in using Distilled water and as Mr Ripley says the Minerals in tap water can collect and damage the the train. In fact I use distilled water in everything like coffee makers humidifiers, trains etc because of mineral deposits that can shorten the life of any appliance. One should always have at least a gallon on hand for such things at its really not that expensive, at least not in my neck of the woods.