When we think of coal cars, we traditionally think “hoppers.” But over the long history of moving coal by rail, many different types of cars have been used. So in the spirit of the season, let’s take a look at what might be bringing the coal to your stocking this year! (No train lover would ever really consider that a bad present after all.)
Early Coal Cars
Coal was among the very first commodities carried by the early steam, gravity and horse-drawn railways of the Nineteenth Century. The first coal cars were the most simple of affairs. Essentially a topless wooden crate with pair of axles beneath it, these small cars held only a few tons of coal at best. Cars were unloaded by hand, or simply toppled over and then put back on the track. Chains served as couplers and brakes…who needs brakes?
As the efficiency of rail transportation and the potential power of steam locomotives became clear however, the need for refinements to these primitive designs were equally obvious. Gondolas would remain the car of choice for the first few decades owing to their simplicity of construction and the fact that hoppers would have to be spotted over some sort of pit or bridge to make gravity unloading practical. But standards, appliances and car capacities all quickly improved.
The first hopper cars, which could unload their contents from doors on the bottom, began to emerge in the 1850s. Prior (and even subsequently) to this there were drop-bottom gondolas which featured a doors in a flat floor. The angled ends (slope sheets) would offer faster unloading however and the lower hopper doors and bays improved both capacity and the cars’ center of gravity.
Wood to Steel
By far, the majority of coal cars produced prior to 1895 were made predominantly of wood. The B&O had experimented with some iron “pots” as early as the 1840s but their tare weight was much too high. It was not until the pressed steel designs of the end of the Century that the railroads could begin to seriously consider steel as an option.
At first railroads were reluctant to switch to steel for its weight and cost. After only a few years in service however, the comparative economics of the more durable material became obvious. While wood remained a common building material for boxcars and reefers for the next several decades, the conversion to steel for hoppers happened relatively quickly. By 1910, with the exception of some composite wood and steel cars during the wars, construction of wood hoppers had nearly completely ended and those that remained in service would be retired over the coming decade.
After the switch to steel, there were numerous variations on the design of coal cars. Some of these were in search for a better construction method, lower tare weights or to address the concerns of specific shippers. Others were centered around increasing the overall capacity of the car. Since you could easily fill a book on the various designs, we’ll focus on the general capacity changes here.
The “standard” car from 1900 to 1960 carried 50 to 55 tons of coal. The 55 ton hopper remained common into the 1970s. There are a variety of reasons this capacity remained the standard for so long. From the shippers’ perspective, this size worked well for a variety of coal uses. Coal for home heating for example was typically shipped in smaller quantities to local distribution centers. Larger consumers still enjoyed the advantage of these small cars by blending several carloads of different grades of coal to get just the formula they demanded.
For the railroads, the size had as much to do about standardization of the dimensions and mechanical parts, in particular the wheels and journals, to make interchange of the coal cars easy among all carriers. There were however clearly cases where a larger hopper offered greater savings.
Next up from the 55 ton car was the 70 ton hopper. These were generally used by larger customers including power and steel companies and for export coal. Although this size of car first showed up in the 1920s, they wouldn’t become a new standard on many lines until the 1960s.
There were also some early experiments into truly enormous coal cars for their day. The most successful of these were 100 and 120 ton gondolas built by the N&W and Virginian. Used only on their own routes for export coal, these “Battleship Gondolas” greatly reduced operating costs between the mines and new rotary car dumpers in Newport News, VA. It was a concept sixty years ahead of its time.
Unit Trains and the Return of the Gondola
By the late 1960s, the economics of coal were changing. While it remained the number one commodity for the railroads, its shipping patterns were changing and coal cars would have to adapt to keep up. Smaller individual car-load shipments were giving way to bulk orders. New competition from government-funded coal slurry pipelines and inland waterways posed a significant threat.
Railroads met the challenge in two ways. First, unit trains offered improved service and much faster turnaround. The efficient dedicated trainload service cut railroad operating costs significantly. Consequently they could pass huge savings onto the big customers to keep them happy.
When these new schedules were combined with new larger equipment, the economic gains were magnified. First 70 ton and then quickly 90 and 100 ton hoppers became the standard. In the span of a decade, the average capacity of a coal car in North America nearly doubled.
The rotary dumper also began to become widely accepted and installed at these major consumers. This rotating platforms could dump 100 tons of coal into the plant in under two minutes. It also meant that the hoppers, especially their mechanical doors, were no longer necessary. Many railroads rebuilt their hoppers into large gondolas to extend their life and reduce operating costs.
Today, the 120 ton capacity gondola is the standard. While you’ll still find plenty of hoppers on the rails for customers who don’t have dumpers (or who prefer the security of knowing their cars can still unload even if the dumper is broken) 100 car trains of these large gons show up regularly on railroads across North America.
The traffic patterns have shifted too. Today the majority of coal used in the United States, and exported from here around the world, comes from the Powder River Basin in Wyoming. PRB coal has even found its way into plants in old-coal states like Pennsylvania and West Virginia. Mines there still fill trains however, including the rich Anthracite fields of eastern Pennsylvania whose product can’t be matched anywhere else. Those modern cars however sure look a lot different from the wooden boxes which descended the gravity switchbacks and inclined planes nearly 200 years earlier.