The origins of the term "Hobo" cannot be traced, but came into common usage by the end of the 19th century. Following the American Civil War, many veterans took jobs building the expanding railroads. Men climbed aboard the freight trains in search of work. In some places, hobos who drifted into town were not always welcome. In other places, they found those who were friendly and willing to help. Knowing where to go or whom to avoid was important to these travelers. So the hobo community developed a written communication system of signs. A symbol on a fence post, mailbox, or tree told other hobos what to expect in the town or from the homeowner. See samples of hobo signs.