1804: The first self-propelling steam locomotive makes its debut at the Pen-y-Darren Ironworks in Wales. The engine successfully carried 10 tons of iron, five wagons and 70 men nearly 10 miles in four hours and five minutes, an average speed of approximately 2.4 mph. However, it was too heavy for the cast iron rails used at the time. The locomotive only ran three trips before it was abandoned. Pictured is a model of the locomotive at the National Waterfront Museum in Swansea, Wales.