W.G. Beattie was the son of Joseph Hamilton Beattie, locomotive engineer for London and South Western Railways (LSWR). He himself joined LSWR in 1862 as a draughtsman, working at Nine Elms Locomotive Works. Following Joseph's death, in 1871, he succeeded his father as Locomotive Engineer at LSWR; however, he was not a success in this post and was forced to resign in 1878.