Jonathan is a 5-ton 60hp Motor Rail "Simplex" 4wDM (Builder's number 11102 of 1959) was built to 24 1/8ins gauge for use by glass manufacturers Pilkingtons for sand extraction operations in southern Lancashire.
With two other "Simplex" locomotives used by Pilkingtons (Anne Marie and Katherine), Jonathan arrived on the Welsh Highland Heritage Railway on 14 December 1981. It has been regauged and painted green.