Railroad
From Conservapedia
A railroad (British: railway) is a form of transport in which vehicles, usually coupled together in groups, travel on rails along fixed routes.
Contents |
History
For a more detailed treatment, see Railroad history.
Pre-locomotive
The use of rails to guide carts, or to provide a smooth roadway, goes back many centuries. In these early railways, waggons were pulled along wooden rails by horses or humans; the main purpose was to move coal (or mineral ores) from mines to navigable waterways.
Because wooden rails wore away quickly, they were replaced by wooden rails with iron plates attached, and later by rails of iron. Cast iron track began to be used in the eighteenth century, although the brittle nature of cast iron meant that such railways could not carry very heavy loads. This consideration also acted against the use of steam engines for motive power.
Steam power
The first steam railway locomotive was designed by Richard Trevithick (1771-1833), a mining engineer from Cornwall, who in 1804 built a locomotive for the Penydarren iron works in south Wales. This proved too heavy for the iron tracks and was converted to a stationary engine. A similar locomotive built by Trevithick for Wylam Colliery in Northumberland also proved too heavy to be of practical use.
William Hedley (1779-1843) aided by another colliery engineer, Timothy Hackworth, built three steam locomotives between 1813 and 1815. These worked successfully until 1828-29, when they were replaced by two more innovative locomotives, including the famous Puffing Billy. Wylam was a true nursery of railway talent.
George Stephenson (1781-1848) was 'the father of the railways'. Although he neither invented railways nor steam locomotion, he made huge improvements to the technology of the latter and was a pioneer in the field of civil engineering for large railway projects. An illiterate miner's son, born in a cottage next to the Wylam colliery railway (as a child, his first job was keeping the line clear of stray animals), he learned to read as a young adult at night classes, obtained a post as engineer at Killingworth Colliery, Northumberland, and there built a number of improved locomotives. He designed the Hetton Railway in County Durham in the early 1820s, at that time the longest railway line in the world, linking a colliery to loading staiths (short piers for pouring coal from wagons on to waiting ships) on the River Wear, and then was appointed engineer to the Stockton and Darlington Railway. The S&DR, which opened in 1825, was the world's first public steam-operated railway, linking the coalfields of SW County Durham to the River Tees at Stockton on Tees. This was not purely a colliery line, but allowed other freight, and even passengers, to be carried. Initially it used both locomotive and horse-drawn trains, though later was converted to steam haulage only.
Stephenson's most famous achievement was the Liverpool & Manchester Railway, opened in 1830 and linking two of the fastest-growing cities of Industrial Revolution England. Although this crossed largely flat terrain, the route involved considerable engineering difficulties, including the crossing of the Chat Moss marshland west of Manchester. Stephenson spent much time, money and effort pouring earth and stone into the marsh to create a firm footing for the railway, without success. He decided instead to build the line upon hurdles of brushwood floating on the bog. The line is still in use.
Isambard Kingdom Brunel (1806–1859) was the world's leading railway engineer of the 1840s and 1850s, credited with bridges and many technical improvements, and more importantly with the idea of a railway as a system for moving people and freight. Brunel set the standard for a very-well-built railway, using careful surveys to minimize grades and curves. That necessitated expensive construction techniques and new bridges and viaducts, and the famous two-mile-long "Box Tunnel." His assistant Daniel Gooch designed the locomotives. One controversial feature was the wide gauge (7 feet, instead of the standard 4'8.5"), which added to passenger comfort but made construction much more expensive and caused difficulties when eventually it had to interconnect with other railways using standard gauge; after his death the gauge was changed to standard.
The opening of the Liverpool & Manchester Railway marked the opening of the 'Railway Age' in Britain and the world. Within three decades most of the major cities in Britain were linked by rail, and railway networks had begun to spread acoss the deveoped nations of the world.
Gauges
The gauge of a railway is the distance between the inside edges of the top of the rails, usually 4' 8.5". Trains are built to operate on a track of a given gauge.
The history of railways is replete with railways being built to a variety of gauges, which has led to numerous problems including limiting the viability of individual railways.
A gauge of four feet eight and a half inches (1435 mm) is generally known as standard gauge, and is widely used around the world. Gauges smaller than this are referred to as narrow gauge and larger gauges are referred to as broad gauge.[1]
Narrow-gauge lines are usually cheaper to construct and have often been used for short industrial lines, connecting branch lines, and places where it would not be economic to construct a more substantial line. However, some narrow gauge lines, such as those of Queensland and South Africa, are built to the same standards as standard gauge lines and perform just like standard-gauge lines.
Safety
Incident statistics
Trains are one of the safest modes of passenger transportation in common use today.
In 2007 in the United States, there were 579,505,279 passenger trips on railroads regulated by the Federal Railroad Administration (excluding urban transit), resulting in 5 fatalities and 1155 injuries, or a fatality rate of approximately 1 per 115 million passengers, and an injury rate of 1 in 500,000.[2]
Issues and problems
grade crossings
Most railroad fatalities occur at crossings or involve trespassers, rather than passengers. In 2007, 851 people died in railroad-related incidents in the United States.[2] Of these, 5 were passengers, 470 were trespassers, and 338 were vehicle occupants or pedestrians at railroad crossings.
Some railroad-crossing collisions occur when a motor vehicle begins to cross railroad tracks while other vehicles are stopped ahead. In order to prevent such accidents, some traffic signals may be designed to provide "[a] special sequence of signal phases and timing to provide additional clearance time for vehicles to clear the tracks prior to the arrival of a train"[3][4]; however, such designs are not mandatory. It is the driver's sole responsibility never to start to cross any railroad tracks until it is certain that both the tracks and the roadway beyond are clear.[5][6]
derailments
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Rail operations
For a more detailed treatment, see Safeworking (railway).
In order to prevent trains from colliding, railroads use electrical signaling systems. The most common systems in use today are based on variations of automatic block signaling, which can be supplemented by positive train control.
automatic block signaling
In automatic block signaling, railroad tracks are divided into sections known as blocks. The signaling system prevents more than one train from occupying any one block at any given time by detecting the presence of trains and by using colored lights (similar to traffic signals) to indicate to train crewmembers whether it is safe to proceed[7]; for example, a yellow signal may be used to instruct train crews to slow down, and a red signal may be used to instruct train crews to stop so as to avoid entering a block that is occupied.
positive train control
Positive train control is a technology by which "automatic control systems" are able "to override mistakes made by human operators" in order to prevent train collisions.[8] Amtrak's Northeast Corridor, for example, uses a system that comprises two elements, "positive train stop" and "civil speed enforcement," which together provide the functionality of positive train control.[8]
Positive train control systems can prevent those collisions that are caused by crewmember inattention to signal indications.[9]
Trains
For a more detailed treatment, see Train.
The vehicles that operate on railways are known as trains, and usually comprise one or more locomotives hauling a number of vehicles.
Further reading
Notes
- ↑ narrow gauge and at broad gauge at AskOxford.com
- ↑ 2.0 2.1 http://safetydata.fra.dot.gov/OfficeofSafety/
- ↑ Manual on Uniform Traffic Control Devices, chapter 4D.
- ↑ See also Manual on Uniform Traffic Control Devices, chapter 8D.
- ↑ See, e.g., Maryland Driver's Handbook, page 103 (page 53 of online edition); Digest of Ohio Motor Vehicle Laws, page 38.
- ↑ See also National Transportation Safety Board Highway/Railroad Accident Report: Collision of Northeast Illinois Regional Commuter Railroad Corporation (METRA) Train and Transportation Joint Agreement School District 47/155 School Bus at Railroad/Highway Grade Crossing in Fox River Grove, Illinois, on October 25, 1995.
- ↑ See Train Control Systems.
- ↑ 8.0 8.1 http://www.ntsb.gov/recs/mostwanted/positive_train.htm
- ↑ See National Transportation Safety Board: statement on positive train control.
Bibliography
- Armstrong, John H. The Railroad: What It Is, What It Does. 4th edition, 1998, Simmons-Boardman Books. ISBN 0-911382-04-6
- Jack Simmons & Gordon Biddle (eds), The Oxford Companion to British Railway History (Oxford 1997)
External links
- Federal Railroad Administration » press room » positive train control
- Railroad Gauge Width, a comprehensive list of railway gauges and countries where they are and were used.
- Guide to Railroad History online
