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Light Rail

Light rail or light rail transit（LRT）is a particular class of urban and suburban passenger railway that uses equipment and infrastructure that is generally less massive than that used for rapid transit systems，with modern light rail vehicles usually running along the system.

Light rail is the successor term to streetcar，trolley and tram in many locales，although the term is most consistently applied to modern tram or trolley operations employing features more generally associated with metro or subway operations，including exclusive rights-of-way，multiple unit train configuration and signal control of operations.

The term light rail is derived from the British English term light railway long used to distinguish tram operations from steam railway lines，and also from its usually lighter infrastructure.

Light rail systems are almost universally operated by electricity delivered through overhead lines，though several systems are powered through different means，such as the JFK Airtrain，which uses a standard third rail for its electrical power，and trams in Bordeaux which use a special third-rail configuration in which the rail is only powered while a tram is on top of it.A few unusual systems like the River Line in New Jersey and the O-Train in Ottawa use diesel-powered trains，though this is sometimes intended as an interim measure until the funds to install electric power become available.

Definition

Most rail technologies，including high-speed，freight，commuter/regional，and metro/subway are considered to be“heavy rail”in comparison.A few systems such as people movers and personal rapid transit could be considered as even“lighter”，at least in terms of how many passengers are moved per vehicle and the speed at which they travel.Monorails are also considered to be a separate technology.Light rail systems can handle steeper inclines than heavy rail，and curves sharp enough to fit within street intersections.They are generally built in urban areas，providing frequent service with small，light trains or single cars.

The most difficult distinction to draw is that between light rail and streetcar or tram systems.There is a significant amount of overlap between the technologies，and it is usual to classify streetcars/trams as a subtype of light rail instead of as a distinct type of transportation.The two common versions are：

1.The traditional type，where the tracks and trains run along the streets and share space with road traffic.Stops tend to be very frequent，but little effort is made to set up special stations.Because space is shared，the tracks are not usually visible.

2.A more modern variation，where the trains tend to run along their own right-of-way and are often separated from road traffic.Stops are usually less frequent，and the vehicles are often got on from a platform.Tracks are highly visible，and in some cases significant effort is used to keep traffic away through the use of special signaling and even grade crossings with gate arms.At the highest degree of separation，it can be difficult to draw the line between light rail and metros，as in the case of London’s Docklands Light Railway，which would likely not be considered“light”compared with London Underground.

Many light rail systems have a combination of the two，with both on road and off road sections.In some countries，only the latter is described as light rail.In those places，trams running on mixed right of way are not regarded as light rail，but considered distinctly as streetcars or trams.

Light rail is usually powered by electricity，generally by means of overhead wires，but sometimes by a live rail，also called third rail（a high voltage bar alongside the track），requiring safety measures and warnings to the public not to touch it.In some cases，especially when initial funds are limited，diesel-powered versions have been used，but it is not a preferred option.Some systems，such as the JFK Airtrain in New York City，are automatic without a driver；however，such systems are not what is usually thought of as light rail.Automatic operation is more common in smaller people mover systems than in light rail systems，where the possibility of grade crossings and street running make driverless operation of the latter inappropriate.

Advantages of light rail

Light rail systems are usually cheaper to build than heavy rail，since the infrastructure does not need to be considerable，and tunnels are usually not required as most metro systems.In addition，the ability to handle sharp curves and steep gradients can reduce the amount of work required.

Traditional streetcar systems and also newer light rail systems are used in many cities around the world because they generally can carry a larger number of people than any bus-based public transport system.They are also cleaner，quieter，more comfortable，and in many cases faster than buses.In an emergency，light rail trains are easier to evacuate than monorail or elevated rapid rail trains.

Many modern light rail projects re-use parts of old rail networks，such as abandoned industrial rail lines.

Disadvantages of light rail

Like all modes of rail transport，light rail tends to be safest when operating in dedicated right-of-way with complete grade separations.Nevertheless，grade separations are not always financially or physically feasible.

In California，the development of light rail systems in Los Angeles and San Jose caused a high rate of collisions between automobiles and trolleys during the 1990s.The most common cause was that many senior citizens were unfamiliar with light rail trolleys and often mistook the trolley“T”signal lights for left-turn signal lights.They would then make a left turn，right into the path of a trolley.The same high crash rate problem existed when the METRORail was first set up in Houston，Texas.

To reduce such collisions，brighter lights and louder warning klaxons have been added to many at-grade crossings.However，consequently，many people do not like to live next to light rail crossings because the noise makes them impossible to sleep.A more effective means of reducing or preventing automobile-light rail collisions has been the installation of quad crossing gates at gate crossings.These gates block both lanes of a street when the gate closes.These prevent those driving automobiles from driving around the gates when they are lowered.

Monorail supporters like to point out that light rail trolleys are heavier per pound of cargo carried than heavy rail cars or monorail cars，because they must be designed to avoid collisions with automobiles.

New Words and Expressions

successor［sək′sesə］　n.　person or thing that comes after and takes the place of（sb./ sth.）　接替的人或事物；后继者；继任者；继承人

locale［ləu′kɑ：l，-′kæl］　n.　scene of events，operations，etc.　（事情发生的）现场，场地

consistently［kən′sistəntli］　adv.　in a systematic or consistent manner　一致地，相符

exclusive［ik′sklu：siv］　adj.　reserved for or limited to the person（s）or group concerned　独有的；独占的

interim［′intərim］　adj.　existing or in force only for a short time；temporary；provisional　暂时的；临时的

intersection［′intə′sekʃən］　n.　a place where roads or other lines meet or cross　交叉

overlap［′əuvə′læp，′əuvəlæp］　n.　a representation of common ground between theories or phenomena　重叠，重复，重合

quad［kwɔd］　n.　（infml）=quadrangle　plane figure with four sides，esp.a square or rectangle　四边形；（尤指）正方形，长方形

people mover　a transport system for moving large numbers of people over short distances，for example by means of a moving platform or along a short track　旅客捷运系统/旅客自动电车输送系统

Notes

1.The Toronto Transit Commission ，or TTC ，is a public transport authority that operates buses，streetcars，and rapid transit lines in Toronto，Ontario，Canada.

2. Suburbs are inhabited districts located either on the outer rim of a city or outside the official limits of a city（the term varies from country to country），or the outer elements of a conurbation.

3. Overhead lines or overhead wires are used to transmit electrical energy to trams，trolley buses or trains at a distance from the energy supply point.These overhead lines are known variously as： OCS（overhead contact system -US & Europe）， OLE（overhead line equipment -UK ），OHW（overhead wiring -AUS ） or Catenary （somewhat inaccurately）.

For the purposes of this article the generic term“overhead line”has been used.Overhead line is designed on the principle of one or more overhead wires situated over rail tracks，raised to a high electrical potential by connection to feeder stations at regular intervals.The feeder stations are usually fed from a high-voltage electrical grid.

4. Air Train JFK is a 13km（largely elevated）rapid transit system in Queens，New York City，connecting the terminals and parking areas at John F.Kennedy International Airport（JFK），Jamaica，and Howard Beach.It is operated by the Port Authority of New York and New Jersey，which also operates the airport and Air Train Newark.

5. Bordeaux is a port city in the south-west of France，with 925，253 inhabitants in the metropolitan area at the 1999 census.It is the capital of the Aquitaine région，as well as the préfecture（administrative capital）of the Gironde département.Its inhabitants are called Bordelais.Bordeaux is also the name of the wine produced in the region surrounding the city.

6. River Line refers to several railroad lines：Conrail’s River Line in northern New Jersey；the London Underground’s Jubilee Line；New Jersey Transit’s River Line in southern New Jersey.

7.The O-Train was introduced in 2001 as a pilot project for light-rail service in Ottawa，Canada，which had long depended exclusively on busways for its high-grade transit service.

8.The term heavy rail is often used for regular railways，to distinguish from systems such as trams/light rail and metro.

Heavy rail typically refers to the standard inter-city rail network，which is built to be robust enough for heavy and high-speed trains，including freight trains，and long distance and high speed passenger trains.Heavy rail is almost always built on its own dedicated right of way and is separate from road traffic.

This distinguishes it from light rail which is built to lightweight construction，carries lightweight trains or trams and which is usually intended for passenger traffic only，usually around cities.

In the United States，the term is used as the general term for metro systems（underground systems and systems that are not running below the ground but are similar to underground systems in other respects）；when the term is used in this way，it should be distinguished from commuter rail and inter-city rail services，which cover longer distances.This usage is seldom found outside the United States；in Britain，the term is instead used to differentiate the standard railway network，particularly the urban and suburban services offered by various national rail companies，from local rail transit systems such as the London Underground and its counterparts.

9. Regional rail systems，or commuter rail systems，usually provide a rail service through a central business district area into suburbs or other locations that draw large numbers of people on a daily basis.The trains providing such services may be termed commuter trains .The development of commuter rail services has become popular today，with the increased public awareness of congestion，dependence on fossil fuels，and other environmental issues，as well as rising automobile costs.

10.A people mover is a fully-automated light rail or tram system.The term is generally used only to describe elevated single-rack loops serving small areas such as airports or theme parks，but is sometimes applied to considerably more complex automated systems.

11. Personal Rapid Transit（PRT） is a transport method that offers on-demand non-stop transportation between any two points on a network of specially built guideways.

PRT has been reinvented many times because it optimizes standard transit-planning math.PRT developers and advocates therefore claim that it will provide more convenient service than cars，with the social advantages of public transport，and excellent environmental and economic benefits.Several PRT systems are in development，and rapid transit using technologies very like PRT is in regular operation.Several PRT designs have been safety-certified by government authorities.Some authorities claim that these developments prove feasibility.

Several PRT proposals have failed dramatically and publicly when their projected costs exceeded their budgets.Other PRT projects have failed technically，some with large monetary losses，often when political needs，schedules or budgets interfered with a technical requirement.As of 2005，there are no true PRT systems in operation，which some believe implies infeasibility.

12.In road transport，an intersection is a place where two roads meet.If there is a grade separation，it is an interchange.

13 1.Right-of-way is a legal term which may have any of several meanings：①The property along the sides of，and including，railroad tracks.Most railroad rights-of-way within the US are called an“exclusive right-of-way”.Persons entering the trackway are either Qualified Roadway Workers or trespassers.②The priority at a crossing，or in traffic.A vehicle must yield either to pedestrians or to other vehicles that have priority.It is not an absolute right as it must be exercised in a reasonable manner with respect for the due care for one’s self and for the care of others involved.

14.The term level crossing （also called： railroad crossing or grade crossing ）is a crossing on one level（or“at grade”）—without recourse to a bridge or tunnel—used to describe the crossing of a railway line by a road，path，or other railroad.

It also applies when a light rail line with separate right-of-way（or a reserved track tramway）crosses a road；the term“metro”usually means by definition that there are no level crossings（i.e.that the system is grade-separated ）.

15.The Docklands Light Railway （DLR）is a light rail public transport metro for the redeveloped Docklands area of eastern London，England.The DLR is separate from the London Underground，having separate tracks and rolling stock.However，the two systems are integrated wherever they meet，and share a single ticketing system.The DLR appears on the London Underground’s Tube Map.

16.The Federal Transit Administration （FTA）within the U.S.Department of Transportation（DOT）provides financial and technical assistance to the local public transit systems.FTA is one of eleven modal administrations within the DOT.Headed by an Administrator who is appointed by the President of the United States，FTA functions through a Washington，DC，headquarters office and ten regional offices which assist transit agencies in all 50 states，the District of Columbia，Puerto Rico，the U.S.Virgin Islands，Guam，Northern Mariana Islands，and American Samoa.

Public transportation includes buses，subways，light rail，commuter rail，monorail，passenger ferry boats，trolleys，inclined railways，and people movers.The Federal government，through the FTA，provides financial assistance to develop new transit systems and improve，maintain，and operate existing systems.

17. A heritage railway or a preserved railway is a term used，especially in Great Britain，for a railway which is run as a tourist attraction and is usually but not always run by volunteers，and seeks to re-create railway scenes of the past.They may be operated in concert with area museums（particularly transport museums）.

18 .A third rail=a live rail： It is a method of providing electricity to power a railroad，typically a mass transit system.

19. METRORail is the light rail service in Houston，Texas that started on January 1，2004.It is the second major light rail service in Texas after the Dallas Area Rapid Transit system.It began operating about 60 years after a previous streetcar system was closed down，making Houston the largest city without a rail system.

METRO Rail is operated by the Metropolitan Transit Authority of Harris County，Texas，or METRO for short.The current track of rail runs through the Texas Medical Center and Downtown Houston.The system’s fleet consists of Siemens-built Avanto vehicles.

20. Klaxon is a trademark for an electromechanical horn or alerting device.The Klaxon’s characteristic “AH-OOOOH-GAH！！ ”sound is produced by a spring-steel diaphragm with a rivet in the centre which is repeatedly struck by the teeth of a rotating cog-wheel.

Exercises

Ⅰ.Answer the following questions according to the text.

1.What’s the definition of light rail？

2.Where is the term“light rail”derived？

3.What are the powers for light rail systems？

4.What are considered to be“heavy rail”？

5.What could be considered as even“lighter”？

6.What advantages does light rail have over heavy rail？

7.Could you draw a distinction between light rail and street car？What’s that？

8.What are the advantages of light rail？

9.What are the disadvantages of light rail？

Ⅱ.Choose the best answer to each question.

1.Most rail technologies，including high-speed，freight，commuter/regional，and metro/subway are considered to be___________.

A.light rail　　B.heavy rail　　C.personal rapid transit　　D.people movers

2.Light rail is generally powered by___________.

A.steam　　B.diesel.　　C.electricity　　D.electromagnet

3.Light rail systems are generally___________to build than heavy rail.

A.cheap　　B.expensil　　C.more expensive　　D.cheaper

4.In an emergency，light rail trains are___________to evacute than monorail.

A.easier　　B.difficult　　C.easy　　D.more difficult

5.Quad crossing gates prevent those driving automobiles from driving around the gates when they are___________.

A.lifted　　B.lowered　　C.reducel　　D.increased

Ⅲ.Translate the following sentences into Chinese.

1.The most difficult distinction to draw is that between light rail and streetcar or tram systems.

2.Light rail is generally powered by electricity，usually by means of overhead wires，but sometimes by a live rail，also called third rail.

3.Automatic operation is more common in smaller people mover systems than in light rail systems.

4.Many modern light rail projects re-use parts of old rail networks，such as abandoned industrial rail lines.

5.Light rail trolleys are heavier per pound of cargo carried than heavy rail cars or monorail cars.

Ⅳ.Summary writing.

In no more than 80 words give an account of this passage.Use your own words as far as possible. hZYPmKwyIwVl6cV6i6EMFUtzfsCBFCG+XiXjtBdwA/+bgTcljchY4xBKmrp1f6Bf