Well, believe it or not freight cars, also known as rolling stock,
actually preceded America’s railroads themselves, first being used in
quarries and coal mines as early as the 1820s. And, as perhaps might be
expected, the very first car designs were simple planks on axles, or the standard flatcar and covered gondolas (a shorter version in height of a boxcar). These first examples were used to carry almost all types of merchandise the railroads handled accept coal and other bulk loads which used “jimmies,” or the predecessor of today’s common open-top hopper cars. As the railroads began to show their superior advantage to horses and
canals in being able to haul large amounts of freight in any type of
weather, it quickly became the preferred mode of transportation by the
mid-19th century. As demand grew so did the need for more specialized
car types and better construction of them.
|A B&O hopper which has escaped the paint shop is on a Norfolk Southern freight at Kannapolis, North Carolina on August 25, 2005.|
Early railroad cars, as mentioned before, were simple things, usually with only one axle attached rigidly to each end of the car. As demand grew it quickly became clear that better designs were needed as these single axle, simple designed cars were very impractical when used to haul heavier and heavier loads (the single-axle cars would bend around curves and by the axles being rigidly mounted to the car’s frame, there was no cushion for the freight, which was often damaged by the time it arrived at its destination).
The two-truck car (two sets of trucks, or wheel housings that hold two axles each, with each car carrying eight total wheels), which is what you commonly see on today’s cars,
were invented as early as the 1830s by the Baltimore & Ohio
Railroad and by the later years of that decade were becoming quite
popular with their ability to more evenly distribute weight (as well as
handle heavier loads), provide better stability for the car, and offer improved cushioning for freight with springs mounted in-between each side of the truck assembly.
|A large load of pipes ride aboard a TTX flatcar, which is a part of NS freight train P40 at Charlotte, North Carolina on July 12, 2007.|
Following the two-truck concept, car technology began
to improve and become larger for heavier and heavier loads as locomotive
horsepower increased and more types of freight were being moved
resulting in better designs needed, although serious research and
development was often hindered by the railroad industry’s conservative
views on such (while railroads have always been conservative and
“archaic” in their views they have also has had their reasons, to some degree,
being that railroading in its very nature has nearly the highest cost
of capital of any industry and relies on economies of scale to be
|A DuPont tanker sits at the yard in Charlotte, North Carolina on April 12, 2006.|
For more information on different railroad car types please click on each link's below:
Unique/Custom Built Designs
In any event, the next major milestone in car development was the switch from wood to steel in construction, which began to appear in cars in the late 19th century, mostly in areas of structural integrity such as sills and trusses. Even though all-steel cars
became favored by the early 20th century, those made of wood remained
in use as late as the 1960s until their age forced them into retirement
(today the Federal Railroad Administration [FRA] has set a 50-year
“shelf life” standard for cars before they must be retired, with roughly ten years between major overhauls while in service).
|An aging wooden Great Northern caboose still looks good as it rides along on a Burlington Northern freight, which is operating over the DM&IR at Iron Junction, Minnesota during August of 1976.|
While cars continue to advance and better designs will continually come about making them of higher quality and able to haul heavier loads, as has been the case since railroads were born (and some railroads have even fabricated their very own cars such as the Baltimore & Ohio and Pennsylvania Railroads) the basic designs will likely continue to fall into one of six categories; gondolas, hoppers, tank cars, well and spine cars, boxcars, and the common flatcar. So, look for these types of freight cars rumbling along on railroad tracks near you throughout the foreseeable future!