I learned that the Golden Spike was the last nail that they put in. The Central Pacific was the slowest one. They were known as the turtle. The Union Pacific were really fast. They were known as the hare. Based on the story, "The Turtle and the Hare". The hare was the fastest and turtle was the slowest. It was really hard for them to build the whole train track. They probably had to make a hole in mountains. They had to break down some trees.