Trains and Railroads
The American Standard
Steam locomotives were introduced in the United States in 1829. They were initially supplied by British builders, but the development of American locomotives moved in a different direction from British and European locomotives almost immediately. Britain was a prosperous, settled country and British tracks were sturdy and well-built, with flat roadbeds and low grades. The Americans, on the other hand, were still pushing the frontier west across a vast landscape. Railroad companies were minimally financed, while striving to web the country with rails. Consequently, American tracks were built hastily, with minimal roadbed preparation. Often they consisted of just flat-topped rails spiked onto roughcut ties. Curves were tighter, grades were steeper, and because the roadbeds were poorly graded if at all, the tracks were uneven. The high performance British locomotives with their fixed, four-wheel suspension did not fare well on U.S. tracks, derailing and breaking axles on the twisting, uneven rails.
The Experiment, a 4-2-0 engine built by John B. Jervis in 1831, was the first locomotive designed specifically for use on the American railroads. To modify the British fixed-wheel suspension, Jervis added a four-wheeled truck mounted on a center pivot to the front of the Experiment. Like the front wheels of a car, this truck could shift and turn with the track, compensating for sharp curves and unevenness. The two drive wheels were at the back of the engine, and the Experiment also boasted the novelty of an enclosed cab.
The design was a success and notion of a leading four-wheel truck was widely adopted in the United States. In 1836, Henry R. Campbell patented the 4-4-0 locomotive. Robust and economical, locomotives of this design could soon be ordered from a number of manufacturers. Add a cowcatcher to sweep away livestock from tracks running through open prairie, and the spark suppressing smokestack that kept glowing cinders from flying out to start fires, and you have the "American Standard," a rugged, powerful locomotive that was ubiquitous in the nineteenth century United States.
Additional accoutrements were added to these engines. Matthias Baldwin was the first to equip a locomotive with warning bells, and George Whistler added the first steam whistle. Night travel was at first accomplished by maintaining a fire on a small car hooked to the front of the engine, but was soon superceded by a headlamp.
Meanwhile, the focus in Britain was on speed. Whereas the average speed of the American Standard was around 25 MPH (40 km/h), British engines were routinely clocking speeds of 60 MPH (97 km/h) as early as 1860. The tracks were flat and smooth with few curves and low grades, and the swift engines were designed with compact, rigid frames and enormous driving wheels. In 1832, Robert Stephenson built the Patentee, a 2-2-0 engine whose design was to dominate in Britain and Europe for many years to come.
Further improvements in steam locomotive technology led to increases in speed and power. To maximize efficiency, double cylinders were constructed in which the steam from the first cylinder was let into a second cylinder to completely exhaust its pushing capabilities. More complete combustion was achieved by installing a fire-brick arch in the firebox that routed air around prior to introducing it to the boiler. To improve power, multiwheel behemoths were built. Locomotives with six and eight wheels were commissioned, as well as the less common 10 to 12 wheelers.
Superheated steam was another method of increasing efficiency. In most early locomotives, steam included a significant portion of what was merely hot water. It was unable to do useful work and took up space in the cylinder where steam could normally expand to do useful work. To address this issue, engineers in Germany and Belgium developed the method of superheated steam. Steam headed toward the cylinders was heated a second time to dry it out, minimizing liquid water content. In tandem with improved cylinder valve gearing, the use of superheated steam increased engine efficiency so much that compound cylinders were eventually phased out as unnecessary.
Steam locomotives reached their peak in the middle of the twentieth century. 4-8-4s and 4-6-4s capable of speeds as high as 95 MPH (153 km/h) were built in the mid-1940s, when rail travel dominated overland passenger travel. Even as these streamliners were capturing the imagination of the public, however, diesel and electric locomotives were beginning to take over rail transportation. By the mid-1950s, the numbers of steam locomotives were dwindling rapidly, and today they exist only as sentimental reminders of a bygone era.
- Trains and Railroads - Diesel And Electric Locomotives
- Trains and Railroads - The First Locomotives
- Other Free Encyclopedias
Science EncyclopediaScience & Philosophy: Toxicology - Toxicology In Practice to TwinsTrains and Railroads - The Steam Locomotive, The First Locomotives, The American Standard, Diesel And Electric Locomotives, Track