This style of steel mill gondola was designed and built by the Geenville Steel Car Company in 1940 for the Erie Railroad. The prototype has a 70 ton capacity with a 52'-6" bed. Its innovative design included drop down ends which allow for even longer cargo. When carrying longer loads it usually travel with flat cars at either end. The flat cars served as "spacers" to allow room for extended cargo. These cars were used to carry just about anything from structual steel components, to lumber and even coal.
This versatile "Greenville-design" car quickly grew in popularity. After WWII numerous railroads purchased the Greenville style mill gondola and became the unofficial industry standard for more than 20 years. Many of these cars remained in service to the late 1970's and some were still in revnue service as late as the early 1980's