An Introduction to North American Freight Train and Rail (part 1)

Other than the movement of passengers, the other function of the train is the movement of freight, and this type of operation in fact preceded not only the concept of passenger transport but also of the locomotive itself, in even its most primitive steam-powered form. In its very earliest days, the railway was employed to facilitate the handling of heavy loads, initially in quarries and mines. In the U.S.A. it was the commercial attractions of collecting the agricultural produce of the country’s westward expansion that first encouraged railroad operators to extend their tracks from the east coast toward the great rivers of the interior. These operators at first planned to run their railroads in much the same way as the operators of toll roads and canals: the operator would provide the tracks, and payment of the requisite fee would allow anyone to haul their own vehicles over them. The concept almost immediately proved ineffective, and the operators took complete control of all elements of the movement. This included the provision of the locomotives; right types of car; depots where goods could be delivered, loaded, unloaded and collected; and the administrative system that made the whole system workable. These are the basic elements that still characterize railroad freight operations.

The same type of locomotives were initially used for both passenger and freight services, but it soon became clear that each type of operation could best be handled by locomotives designed and built for that task. Passenger services required the use of locomotives optimized for speed rather than power as the loads were comparatively light, while freight services needed locomotives optimized for power rather than speed as the loads were heavier. In practical terms, this led to the development of the freight locomotive with driving wheels that were more numerous but smaller in diameter than those of locomotives optimized for the movement of passengers.

With speed a relatively insignificant factor in freight operations, except when perishable agricultural produce was involved, the primary requirement in freight operations became the movement of the maximum possible quantity of freight in each train. Some notably enormous steam locomotives were created and manufactured specifically to work vast freight trains, but the introduction of the diesel engine was a major milestone in freight operations, for at last it was possible to locate the motive power away from a single point. During the period of steam locomotion, when it had generally been impossible to locate the power anywhere but at the head or tail of the string of freight cars, the size of the freight train was limited by the load that could be supported by the couplings. Then the advent of the diesel-engined power unit opened the way for remote control of a number of power units, making it possible for slave locomotives to be located at intervals along the train and so spread the load and balance the power that had to be exerted.

An earlier breakthrough in the control of long trains was the introduction of the quick-acting airbrake. At first, freight ears were individually braked, which required the brakeman to move along the roofs of the cars to reach the wheels by which the brakes were controlled: this was a slow and inefficient system, and one fraught with danger to brakemen, many of whom were killed. What was needed was a system that allowed the brakes to be controlled from a single point in the locomotive, making it feasible for the brakes in every car to be applied simultaneously By the 1870s the Westinghouse type of airbrake, offering this capability was entering large-scale service in passenger trains. The introduction of Westinghouse airbrakes in freight trains, especially those of greater length, was initially less successful as the time required for the braking force to be transmitted along the full length of the train could lead to severe shocks in the rearmost cars. By the mid a version of the Westinghouse airbrake system with the capacity for quicker action had been developed, and its use made it possible for long trains to be stopped without significant delay or shocks.

History of North American Freight Rail:
Pt. 1  2  3  4  5  6

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Updated: Sunday, 2017-01-01 20:42 Pacific Standard Time