No.8 King Arthur is a coal fired 0-6-2 tank engine. Works No. 324 it was built in 2005 by Exmoor Steam Railway. It is one two locomotives of this type to have been built at Exmoor. At 41 inches wide and 5 foot high, this is the largest engine that can run on this size of railway.

This engine is one of the most powerful conventional steam engines of this track gauge in the World. It was given the name King Arthur as part of a theme around the legends of King Arthur on its arrival at Rudyard. It was designed to pull any possible train that may be required at Rudyard and has been completely successful. King Arthur has 2 cylinders 4.75 inch bore X 7.5inch stroke. The boiler pressure is 150 Pounds per square inch and it has 13 inch diameter driving wheels. The valve gear has roller bearings throughout as do the axle boxes. It was built to be re-gaugeable to 12.25 inch gauge if required.

King Arthur has run every year since its arrival in 2005. It has needed very little other repair work. A complete overhaul was undertaken in 2015. The main improvement to the engine was the fitting of a new fire hole door and a special steel firebox arch. This greatly improved coal consumption. A major overhaul was completed in 2019 together with a repaint, and the boiler was re-tubed in 2020.