For the first hundred years or so of railroad history, dry bulk items such as sand and cement were put into bags or boxes and loaded into boxcars for shipment. This process required considerable labor to load and unload. In the 20th century a new type of car, the covered hopper, was developed. As the name implies, these cars were essentially an open top hopper with a roof and hatches added for loading. At first they were just used for special commodities, while cement was still hauled in boxcars. This began to change dramatically in the late 1940's as the railroads ordered more and more covered hoppers. By the 1970's almost all dry bulk items from sand to grain to plastic pellets were shipped in covered hoppers.

One of the more important builders of covered hoppers was American Car & Foundry (ACF). The first ACF covered hoppers were rib-side cars, like many others of the time. In the 1960's ACF eliminated the supporting ribs and started building what they called the Center Flow hopper with a smooth, rounded side. The cars were built at several ACF plants, but the Huntington, West Virginia plant built only Center Flow cars since their inception and was the primary builder.

These cars have been riding the rails since the 1960's and have been seen all over North America in a huge number of schemes. Today, many examples still ride the rails and will for years to come.

Features:

• Round or trough hatches
  
• Photo-etched metal roof walk
  
• Separately applied wire grab irons and stirrup steps
  
• Separate brake cylinder, valve and air reservoir with wire brake plumbing
  
• Detailed outlets
  
• Fully-assembled and ready-to-run out of the box
  
• Accurately painted and printed
  
• Highly detailed, injection molded body
  
• Separately applied brake wheel
  
• Machined metal wheels
  
• Screw mounted trucks
  
• Body mounted McHenry operating scale knuckle couplers
  
• Weighted for trouble free operation
  
• Wheels with RP25 contours operate on all popular brands of track
  
• Minimum radius: 18”