The dawn of the locomotive meant better-equipped armies during wartime, longer battles, and more casualties. Trains were part of the problem, but also part of the solution. During the Crimean and American Civil War, locomotives not only transported soldiers to the front lines, but also picked up and cared for the wounded on the return trip. See how these ambulance trains were used in the 19th century and during World War I, and learn how doctors and nurses worked around the clock to provide care while rolling in and out of war zones.