The Great Southern Railways Class 800 steam locomotives were built principally for express passenger work on the Dublin to Cork main line of that company. These locomotives were designed under the supervision of E. C. Bredin with his Chief Draughtsman, H. J. A. Beaumont, preparing the drawings. They were the largest and most powerful engines ever to run in Ireland by quite a large margin, and the only three express passenger locomotives to be built in an independent Ireland.