Whistling Billy was an eight-ton, short-wheel base, wood burning locomotive built by the H. K. Porter Co. of Pittsburg, Pennsylvania, and delivered to the Merced Mining Company of Coulterville in 1897. All of Billy's active life was spent hauling gold-bearing quartz ore over narrow-guage tracks from the Mary Harrison mine south of town to the Potosi stamp mill west of town, a distance of about four miles. Abandoned in 1904, it was resurrected in the mid 1930's.