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A '''railroad''' (British: '''railway''') is a form of [[transport]] in which trains are pulled on [[railway track|rails]] along fixed routes carrying freight or passengers. Emerging from small-scale horse-drawn operations combined with the steam engine, railroads were developed in Britain after 1830 to become the iron workhorse of the [[Industrial Revolution]]. Thanks to safety measures and signals, accident rates were kept low. Diesel and electric engines in the 20th century improved efficiency, bit the railroads lost most of their traffic to trucks, buses and other new forms (such as airplanes and pipelines) in the 20th century. Today railroads mostly handle bulk freight, such as coal and containers. It is cheaper to move coal by rail to electric power plants than to burn the coal near the mines and move the electricity.

A '''railroad''' (British: '''railway''') is a form of [[transport]] in which [[train]]s are pulled on [[railway track|rails]] along fixed routes carrying freight or passengers. Emerging from small-scale horse-drawn operations combined with the steam engine, railroads were developed in Britain after 1830 to become the iron workhorse of the [[Industrial Revolution]]. Thanks to safety measures and signals, accident rates were kept low. Diesel and electric engines in the 20th century improved efficiency, but the railroads lost most of their traffic to trucks, buses and other new forms (such as airplanes and pipelines) in the 20th century. Today railroads mostly handle bulk freight, such as coal and containers. It is cheaper to move coal by rail to electric power plants than to burn the coal near the mines and move the electricity.

 

:Painted stations whistle by ...

[[Image:Csx_railroad.jpg|thumb|300px|A CSX freight train]]

[[Image:Csx_railroad.jpg|thumb|300px|A CSX freight train]]

== Gauges ==

== 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 ''gauge'' of a railway is the distance between the inside edges of the top of the rails, usually 4' 8.5". [[Train]]s 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.

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.

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.<ref name="FRA statistics" />  Of these, 5 were passengers, 470 were trespassers, and 338 were vehicle occupants or pedestrians at railroad 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.<ref name="FRA statistics" />  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 [[car|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"<ref name="4D13">''Manual on Uniform Traffic Control Devices'', [http://mutcd.fhwa.dot.gov/htm/2003r1r2/part4/part4d.htm#section4D13 chapter 4D].</ref><ref name="8D07">''See also'' ''Manual on Uniform Traffic Control Devices'', [http://mutcd.fhwa.dot.gov/htm/2003r1r2/part8/part8d.htm#section8D07 chapter 8D].</ref>; 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.<ref name="driver handbooks">''See'', ''e.g.'', [http://mva.state.md.us/Resources/DL-002B.pdf ''Maryland Driver's Handbook''], page 103 (page 53 of online edition); [http://www.bmv.ohio.gov/pdf_forms/HSY-7607.pdf ''Digest of Ohio Motor Vehicle Laws''], page 38.</ref><ref name="HAR-9602">''See also'' National Transportation Safety Board ''[http://www.ntsb.gov/publictn/1996/HAR9602.pdf 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''.</ref>

Some railroad-crossing collisions occur when a [[car|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";<ref name="4D13">''Manual on Uniform Traffic Control Devices'', [http://mutcd.fhwa.dot.gov/htm/2003r1r2/part4/part4d.htm#section4D13 chapter 4D].</ref><ref name="8D07">''See also'' ''Manual on Uniform Traffic Control Devices'', [http://mutcd.fhwa.dot.gov/htm/2003r1r2/part8/part8d.htm#section8D07 chapter 8D].</ref> 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.<ref name="driver handbooks">''See'', ''e.g.'', [http://mva.state.md.us/Resources/DL-002B.pdf ''Maryland Driver's Handbook''], page 103 (page 53 of online edition); [http://www.bmv.ohio.gov/pdf_forms/HSY-7607.pdf ''Digest of Ohio Motor Vehicle Laws''], page 38.</ref><ref name="HAR-9602">''See also'' National Transportation Safety Board ''[http://www.ntsb.gov/publictn/1996/HAR9602.pdf 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''.</ref>

==== derailments ====

==== derailments ====

{{main|Safeworking (railway)}}

{{main|Safeworking (railway)}}

In order to prevent trains from colliding, railroads use electrical signaling systems.  The most common systems in use in the united states are based on variations of [[automatic block signaling]], which can be supplemented by [[positive train control]].

In order to prevent trains from colliding, railroads use electrical signaling systems.  The most common systems in use in the United States are based on variations of [[automatic block signaling]], which can be supplemented by [[positive train control]].

==== Automatic block signaling ====

==== 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 signal]]s) to indicate to train crew whether it is safe to proceed<ref name="train control systems">''See'' [http://www.ntsb.gov/events/symp_ptc/presentations/03_VanderClute.pdf Train Control Systems].</ref>; 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.

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 signal]]s) to indicate to train crew whether it is safe to proceed;<ref name="train control systems">''See'' [http://www.ntsb.gov/events/symp_ptc/presentations/03_VanderClute.pdf Train Control Systems].</ref> 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 ====

<references/>

<references/>

==see also==

==See also==

* [[Railway history]]

* [[Railway history]]

===Bibliography===

===Bibliography===