The world's smallest republic with a population of a bit over 9,000, Nauru is a 21 square-kilometre (8 square miles) oval-shaped island in the southwestern Pacific Ocean, 42 km (26 miles) south of the Equator. The first railway in Nauru was opened in 1907, a 2 ft (610 mm) gauge 3.9 km long line serving the phosphate mining industry. The stamp of the small loco mounted on a plynth was one of those first used. Orenstein & Koppel was one of the locomotive suppliers. The line was converted to 3 ft (914 mm) gauge in 1920. The artwork shows a Clyde diesel. Phosphate mining ended a few years ago and so did the railway.