The First Transcontinental Railroad was built in the 1860’s. The main line was officially completed on May, 10 1869. He connects the well-developped rail network on the east coast with California. The railroad was build so as to connect the rail network of the east to the pacific coast during the American Civil war ! He’s considered by some to be the greatest technological feat of the 19th century. It ended the centuries old way of life of the native americans and greatly altered the environement.