Hopper cars evolved from gondolas in the mid-19th Century as doors were added to the floors of the cars for easier unloading. By extending these doors further below the floor, capacity was increased and the car’s center of gravity was lowered. Sloping sides made unloading more efficient. Although it meant customers would need to raise the tracks or build pits beneath them to utilize the cars, the labor savings quickly outweighed these costs.
Around the turn of the century, the first steel cars were introduced. Despite the extra weight and cost of the cars, increased capacity and longevity made the cars preferable. Composite (wood and steel) cars remained in use through WWII however. Since the change to steel, the most noticeable change in hopper design has been in size and capacity. Another interesting adaptation, begun in the 1930s, was the addition of a roof to the car. We’ll look at covered hoppers in a coming week.
Although hoppers are primarily associated with coal, they can carry many other loads as well. Iron ore, crushed stone, coke, wood chips, and scrap are other common loads. One of the more unique loads for a hopper was probably snow. Snow cleared from northern city streets would be loaded into hoppers and routed, well anywhere south! The cars would unload themselves in transit.
Today, hoppers remain one of the most common freight cars on the rails – with coal service dominating. The number of hoppers has been diminished in recent decades however by the increased use of, ironically, gondolas. With more and more customers using rotary dumpers to unload cars, simplicity in design again rules the day. Even still, hoppers will remain common sights on the rails, and on our layouts, well into the future.