|Colorado Unit Coal Trains 2000-Present|
|General Overview of Dual Purpose Hopper Types|
|The most versatile coal cars in operation are the dual purpose hoppers. They can be used in bottom dump or rotary dump operations. This style of cars is popular with large utilities who pool cars between multiple power plants thus requiring the car fleet to be capable of either bottom dump or rotary dump operation.
There are a few disadvantages to dual purpose hoppers. The main one is the limitation in capacity compared to rotary gondolas. A typical modern coal hopper has a load capacity of about 236,000 lbs whereas a comparable rotary gondola can carry 244,000 lbs. Although that's only a difference of 8,000 lbs between the cars, on a 125-car unit train that amounts to a difference of 1,000,000 lbs of capacity! Economies of scale still favor high-capacity rotary gondolas in this case. As noted earlier, rotary gondolas are also generally cheaper to purchase and cheaper to maintain.
XCLC 060888 is an example of a typical dual-purpose hopper. It's your generic modern aluminum-bodied automatic-dump hopper equipped with a rotary coupler on one end (indicated by the red end marker).
AMTX 10001 is a dual-purpose hopper equipped with two rotary ends.
CEFX 62321 is an interior-post version of the dual-purpose car type. Here we get a good look at the discharge gates in their open position.