The High Line was authorized in 1929 and, five years and $150 million later, stretched 13 miles through the city. It actually passed through buildings and factories, allowing for easy loading and unloading without disturbing the streets below.
This was a huge improvement over the original transportation artery—a street level railroad that became known as the "Death Avenue" due to the frequency of accidents between trains and other traffic.
The accidents were so bad, in fact, that the city hired a team of horsemen to escort trains down the tracks. These men were called "West Side Cowboys."