 Led by Andrew Carnegie, a railroad was built circumventing Baltimore, allowing soldiers to arrive on April 25, thereby saving the capital.Thousands of raw volunteers (as well as many professional soldiers) came to the area to fight for the Union.By the mid-summer, Washington teemed with volunteer regiments and artillery batteries from throughout the North, all serviced by what was little more than a country town of what had been in 1860, 75,800 people.