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7.	AC systems ...	g)	a power supply that the trains can access at all
			times.
8.	The third rail system uses a shoe ...	h)	always use overhead wires
9.	The running rails have ...	i)	either an overhead wire or a third rail

Ex.4. Go back to the text and using the paragraph reference find words which are similar to:

broad, depending on, position, only just (paragraph 1); speeding-up, standard, basic, complicated (paragraph 2); fast, multitude (paragraph 3);

previous, last, easy, lately (paragraph 4); with the help of, additional (paragraph 5); slid, adhered (paragraph 6);

gear, arises, likeness, by means of (paragraph 7).

U N I T 2

Ex. 1. Copy and memorize the following terms.

Glossary

conduit – изоляционная трубка pickup – токосниматель plough ( plow ) – токосниматель shield – экран

Ex. 2. Copy the following words and memorize their meanings:

9approach – подход

9articulated – сочленённый

9disruption – разрушение; нарушение

9evidence – наглядность, очевидность

9flush with … – на одном уровне с …

9hitherto –до сих пор

9hood – кожух

9option – вариант

9passage – прохождение

9pedestrian– пешеход

9remainder – оставшаяся часть

9slope – уклон

9slot – щель

9to abandon – покидать; прекращать использовать

9to favour – благоприятствовать

9to pave – мостить

9to tread (trod / trodden) – идти

9unsightly – неприглядный

9vulnerable – уязвимый

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Ex. 2. Translate the following sentences from English into Russian.

1. Of course I don't want to abandon ship. 2. There was severe disruption to the gas, water and electricity supplies. 3. Make sure that the cupboard is flush with the wall. 4. He decided to adopt a different approach and teach the Bible through story-telling. 5. There are a number of options available. 6. The bridge isn't strong enough to allow the passage of heavy vehicles. 7. She trod barefoot on the soft grass. 8. We work mainly with the elderly and other vulnerable groups. 9. The city centre streets are paved with dark local stone. 10. In California the definition of a pedestrian has been broadened to include anyone on any human powered vehicle that is not a bicycle, as well as people operating self-propelled wheelchairs by reason of physical disability. 11. Alan dropped another coin into the slot on the pay phone. 12. An articulated vehicle has two parts joined together to make it easier to turn. 13. The current economy does not favour the development of small businesses. 14. He spent the remainder of his police career behind a desk. 15. She looked back up the grassy slope. 16. French astronomers have found a hitherto unknown galaxy. 17. A fume hood is typically a large piece of equipment enclosing five sides of a work area, the bottom of which is most commonly located at a standing work height. 18. Rising gas prices in the 1970s forced the corporation to abandon the project.

Ex. 3. Translate the following sentences from English into Russian paying attention to participles.

1. They tried to find out the laws of evolution operating on each species. 2. All exposed skin should be covered with protective cream. 3. Pipes may need insulating hood against the cold. 4. A thermal bag is a type of insulated shipping container. 5. At the conference they discussed problems associated with cancer treatment. 6. The ruin of the empire caused by the loss of freedom and the growth of despotism resulted in the goth’s ivasion. 7. The road was blocked by a fallen tree. 7. The car was found abandoned in Bristol. 8. Divorced men can too easily become disconnected from their children. 9. Witness statements presented a confused picture of the incident. 10. Jointed rails were used, at first because the technology did not offer any alternative. 11. A major goal of overhead power line design is to maintain adequate clearance between energized conductors and the ground so as to prevent dangerous contact with the line. 12. Add the remaining ingredients and simmer for 30 minutes. 13. Articulated trams, invented and first used by the Boston Elevated Railway in 1912-13 have two or more body sections, connected by flexible joints and a round platform at their pivoting midsections. 14. By contrast, trams in parts of continental Europe continued to be used by many cities, although there were contractions in some countries, including the Netherlands. 15. Structures for overhead lines take a variety of shapes depending on the type of line.

Ex. 4. Choose the right participle. Translate the sentences from English into Russian.

1.Power transfer into a linear balancing / balanced load is constant, which helps to reduce generator and motor vibrations.

2.A three-phase induction motor has a simple design, inherently high starting / started torque and high efficiency.

3.These types of loads do not require the revolving / revolved magnetic field characteristic of three-phase motors but take advantage of the higher voltage and power level usually associating / associated with three-phase distribution.

4.Some railway locomotives are moving to multi-phase motors driving / driven by such systems even though the incoming / income supply to a locomotive is nearly always either DC or single-phase AC.

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5.Another method often attempted is with a device referring / referred to as a static phase converter.

6.A split phase electricity distribution system is a 3-wire single-phase distribution system, commonly using / used in North America for single-family residential and light commercial (up to about 100 kVA) applications.

7.A transformer supplying / supplied a 3-wire distribution system has a single-phase input (primary) winding.

8.No individual conductor will be at more than 120 V potential with respect to earth, reducing / reduced the earth fault current when comparing / compared to a 240 V, 2- wire system that has one leg (the neutral) earthed.

9.A fully electrifying / electrified railway has no need to switch between methods of traction thereby making / made operations more efficient.

10.Six of the most commonly using / used voltages have been selected for European and international standardisation.

11.These standards take into account the number of trains drawing / drawn current and their distance from the substation.

12.At the end was a complicated suburban and outer-suburban network of lines, emanating / emanated from London Bridge and Victoria stations, as well as shared interests in two cross-London lines.

13.During the 1860s the line began to develop a new traffic among the growing / grown number of middle-class commuters who were beginning to live in the south London suburbs, whilst working in London.

14.The Great Northern was the only privately funding / funded, and successfully built, transcontinental railroad in United States history.

15.Many of the structures have been listed on the National Register of Historic Places due to unique construction, location and the beauty of the surrounding / surrounded regions.

16.On locomotives equipping / equipped with regenerative brakes, descending / descended gradients require very little use of air brakes as the locomotive's traction motors become generators sending / sent current back into the supply system.

Read the text and translate it using a dictionary if necessary.

T H I R D R A I L

Most electrification systems use overhead wires, but third rail is an option up to about 1,200 V. While use of a third rail does not require the use of DC, in practice all third-rail systems use DC because it can carry 41% more power than an AC system operating at the same peak voltage. Third rail is more compact than overhead wires and can be used in smallerdiameter tunnels, an important factor for subway systems.

Third rail systems can be designed to use top contact, side contact or bottom contact. Top contact is less safe, as the live rail is exposed to people treading on the rail unless an insulating hood is provided. Sideand bottom-contact third rail can easily have safety shields incorporated, carried by the rail itself. Uncovered top-contact third rails are vulnerable to disruption caused by ice, snow and fallen leaves.

DC systems (especially third rail systems) are limited to relatively low voltages and this can limit the size and speed of trains and cannot use low-level platform and also limit the amount of air-conditioning that the trains can provide. This may be a factor favouring overhead

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wires and high voltage AC, even for urban usage. In practice, the top speed of trains on thirdrail systems is limited to 100 mph (160 km/h) because above that speed reliable contact between the shoe and the rail cannot be maintained.

Some street trams (streetcars) used conduit third-rail current collection. The third rail was below street level. The tram picked up the current through a plough (U.S. "plow") accessed through a narrow slot in the road. In the United States, much (though not all) of the former streetcar system in Washington, D.C. (discontinued in 1962) was operated in this manner to avoid the unsightly wires and poles associated with electric traction. The same was true with Manhattan's former streetcar system. The evidence of this mode of running can still be seen on the track down the slope on the northern access to the abandoned Kingsway Tramway Subway in central London, United Kingdom, where the slot between the running rails is clearly visible, and on P and Q Streets west of Wisconsin Avenue in the Georgetown neighborhood of Washington DC, where the abandoned tracks have not been paved over. The slot can easily be confused with the similar looking slot for cable trams/cars (in some cases, the conduit slot was originally a cable slot). The disadvantage of conduit collection included much higher initial installation costs, higher maintenance costs, and problems with leaves and snow getting in the slot. For this reason, in Washington, D.C. cars on some lines converted to overhead wire on leaving the city center, a worker in a "plow pit" disconnecting the plow while another raised the trolley pole (hitherto hooked down to the roof) to the overhead wire. In New York City for the same reasons of cost and operating efficiency outside of Manhattan overhead wire was used. A new approach to avoiding overhead wires is taken by the "second generation" tram/streetcar system in Bordeaux, France (entry into service of the first line in December 2003; original system discontinued in 1958) with its APS (ground current feed). This involves a third rail which is flush with the surface like the tops of the running rails. The circuit is divided into segments with each segment energized in turn by sensors from the car as it passes over it, the remainder of the third rail remaining "dead". Since each energized segment is completely covered by the lengthy articulated cars, and goes dead before being "uncovered" by the passage of the vehicle, there is no danger to pedestrians. At least initially there were teething troubles in terms of maintaining current feed, however, and the fact that the system is used exclusively in the historic center, with the cars on leaving this zone converting to conventional overhead pickup, underlines how, esthetics aside, for streetcars/trams it is hard to beat the overhead wire system in terms of overall efficiency.

Ex. 5. Go back to the text and translate the following phrases into Russian:

operating at the same peak voltage, people treading on the rail, safety shields incorporated, vulnerable to disruption caused by, relatively low voltages, a factor favouring overhead wires and high voltage AC, reliable contact between the shoe and the rail, clearly visible, abandoned tracks, similar looking slot, disconnecting the plow, converting to conventional overhead pickup.

Ex. 6. Choose the right alternative to complete the sentences. You may consult the text.

1.	Most electrification systems use ....
	a) third rail	b) overhead wires	c) underground cables
2.	All third-rail systems use DC because it ....
	a) is more economical	b) is more reliable

c) can carry more power than an AC system.

3.Top contact is ....

a) more dangerous

b) less dangerous

c) more convenient

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4.	Sideand bottom-contact third rail incorporate ....
	a) an insulating hood	b) safety shields	c) conduit slots
5.	Third rail systems are limited to ....
	a) low voltages	b) low resistance	c) low capacitance

6.A factor favouring overhead wires and high voltage AC is ....

a)use of low-level platforms

b)limited amount of air-conditioning that the trains can provide

c)limited size and speed of trains

7.The top speed of trains on third-rail systems is limited to ....

a) 100 km/h

b) 160 mph

c) 160 km/h

8.The disadvantage of conduit collection included ...

a)higher manufacturing costs, higher maintenance costs, and problems with water getting in the slot.

b)higher initial installation costs, higher maintenance costs, and problems with leaves and snow getting in the slot.

c)higher initial installation costs, higher operational costs and problems with leaves and snow getting in the slot.

Ex. 3. Translate the following sentences from Russian into English.

Контактный рельс – это жёсткий контактный провод, предназначенный для осуществления скользящего контакта с токоприёмником подвижного состава (электровоза, моторного вагона). Главное преимущество контактного рельса - надёжное токоснимание при контакте с токоприёмниками моторных вагонов или электровозов, расположенными на колёсных тележках. исключаются колебание токоприёмников и отрыв их от контактного рельса, а следовательно, нарушение контакта и разрыв цепи тока, искрение и дугообразование. Основная область применения контактных рельсов - подземный железнодорожный транспорт, в частности, обеспечение движения поездов метрополитена. Реже данное технологическое решение применяется на открытых линиях при относительно невысоком напряжении. Различают два типа контактных рельсов:

•боковой контактный рельс закрыт сверху и с боков изоляционным коробом, а электропитание снимается проходящим снизу контактным башмаком (нижний токосъём).

•в нижнем контактном рельсе изоляция отсутствует.

Взависимости от того, как расположена контактная поверхность, имеют место: нижний токосъём – это контактная поверхность снизу; верхний токосъём – контактная поверхность сверху; боковой токосъём – контактный рельс повёрнут на 90 градусов, в результате чего контактная поверхность находится сбоку.

A d d i t i o n a l t e x t

Read the text and translate it using a dictionary. Check your translating speed.

F O U R T H R A I L

Arcs like this are normal and occur when the collection shoes of a train drawing power reach the end of a section of power rail. With top-contact third (and fourth) rail a heavy shoe suspended from a wooden beam attached to the bogies collects power by sliding over the top surface of the conductor rail.

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The London Underground in England is one of the few networks that uses a four-rail system. The additional rail carries the electrical return that, on third rail and overhead networks, is provided by the running rails. On the London Underground, a top-contact third rail is beside the track, energized at +420 V DC, and a top-contact fourth rail is located centrally between the running rails at −210 V DC, which combine to provide a traction voltage of 630 V DC. The same system was used for Milan's earliest underground line, Milan Metro's line 1, whose more recent lines use an overhead catenary.

This scheme was introduced because of the problems of return currents, intended to be carried by the earthed (grounded) running rails, flowing through the iron tunnel linings instead. This can cause electrolytic damage and even arcing if the tunnel segments are not electrically bonded together. The problem was exacerbated because the return current also had a tendency to flow through nearby iron pipes forming the water and gas mains. Some of these, particularly Victorian mains that predated London's underground railways, were not constructed to carry currents and had no adequate electrical bonding between pipe segments. The four-rail system solves the problem. Although the supply has an artificially created earth point, this connection is derived by using resistors which ensures that stray earth currents are kept to manageable levels.

London's sub-surface underground railways also operate on the four-rail scheme since in a number of areas (for example the Piccadilly Line and Metropolitan Line services to Uxbridge) sub-surface and deep-level stock run on the same tracks.

On tracks that London Underground share with National Rail third-rail stock, the centre rail is connected to the running rails, allowing both types of train to operate, at a compromise voltage of 660 V. Underground trains pass from one section to the other at speed; lineside electrical connections and resistances separate the two types of supply.

Fourth-rail trains occasionally operate on the National third-rail system. To do so, the centre-rail shoes are bonded to the wheels. This bonding must be removed before operating again on fourth-rail tracks.

A system proposed (but not used) by the South Eastern and Chatham Railway around 1920 was 1,500 V DC four rail. Technical details are scarce but it is likely that it would have been a mid-earth system with one conductor rail at +750 V and the other at −750 V. This would have facilitated conversion to 750 V DC three-rail at a later date.

A few lines of the Paris Métro in France operate on a four-rail power scheme but for a very different reason. It is not strictly a four-rail scheme as they run on natural rubber tyres running on a pair of narrow roadways made of steel and, in some places, concrete. Since the tyres do not conduct the return current, two conductor rails are provided outside of the running 'roadways', so at least electrically it fits as a four-rail scheme. The trains are designed to operate from either polarity of supply, because some lines use reversing loops at one end, causing the train to be reversed during every complete journey, to save having to "change ends" by having the operator walk to the other end of the train to make the former last car the lead car in the new direction.

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U N I T 3

Ex. 1. Copy and memorize the following terms.

Glossary

booster transformer – вольтодобавочный трансформатор depot – станция, депо

dropper wire струна контактного провода feeder station – питающая станция

mast – мачта

overhead catenary – цепная подвеска электрической железной дороги overhead lines (wires) - воздушная контактная сеть

return conductor – обратный провод support post – опорный столб suspension – подвеска

track magnet – путевой индуктор

Ex. 2. Copy the following words and memorize their meanings:

9awkward – неудобный

9groove – паз

9hostile – враждебный

9laterally – сбоку, в сторону

9obsolete – вышедший из употребления

9precaution – мера предосторожности

9roughly – приблизительно

9tension – напряжение, напряжённость

9to aggravate – ухудшать

9to bounce – отскакивать

9to justify – оправдывать

9to kink – запутываться

9to overlap – перекрывать

9to sag– провисать

9to suffice – быть достаточным

9to wander – прогуливаться

9to withstand – выдержать

9to worsen – ухудшать

Ex. 3. Translate the following sentences from English into Russian.

1. The bolt slid easily into the groove. 2. Her limbs were splayed at angles too awkward for comfort. 3. Southampton fans gave their former coach a hostile reception. 4. Ministers must appear before parliament and justify their actions. 5. The wall is weak and requires to be supported laterally. 6. Building the new road will only aggravate the situation. 7. The ball bounced off the post and into the goal. 8. He was found wandering the streets of New York. 9. There were roughly 200 people there. 10. Will computers make books obsolete? 11. This fabric can withstand steam and high temperatures. 12. A few brief observations will suffice for present purposes. 13. The branch sagged under the weight of the apples. 14. A lot of teachers expect the situation to worsen over the next few years. 15. Take care to avoid kinking the wire. 16. There was a lot of tension on the wire before it snapped. 17. The second phase of

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development overlaps the first. 18. Save your work often as a precaution against computer failure. 19. The single currency is in trouble, and the problem is worsening.

Ex. 2. Fill in the blanks with the words given in the box. Translate the sentences.

pantographs	return conductor	shoe	third rails
dropper wires	catenary short circuits	tension	feeder stations
masts	depot	collection	overhead lines
	booster transformers

1. Overhead line is designed on the principle of one or more overhead wires or rails situated over rail tracks, raised to a high electrical potential by connection to ... at regular intervals. 2. Overhead pantographs are sometimes used as alternatives to … because third rails can ice over in certain winter weather conditions. 3. There has to be a complete circuit, from the source of the energy out to the train and back to the source, so a … is needed for our railway. 4. Catenary wire is attached to the contact wire at regular intervals by vertical wires known as

.... 5. The whole overhead catenary system is subjected to a mechanical.... 6. …. areas tend to have only a single wire and are known as simple equipment. 7. Dropper wires traditionally only provide physical support of the contact wire, and do not join the ..., and contact wires electrically. 8. There are and were some railways that used two or three ..., usually to carry three-phase current to the trains. 9. All systems of multiple overhead lines have the disadvantage of high risk of ... at switches and therefore tend to be impractical in use, especially when high voltages are used or when trains run through the points at high speed. 10. As the train moves, the contact ... slides along the wire and can set up acoustical standing waves in the wires which break the contact and degrade current collection. ... with overhead wires are now the dominant form of current collection for modern electric trains because, although more expensive and fragile than a third-rail system, they allow the use of higher voltages.

11.Catenary ... are located outside the drains and, beyond them, there is a walkway area.

12.Queensland uses 25 kV AC overhead traction with ... in the Brisbane suburban area and auto transformers elsewhere. 13. To achieve good high-speed current ..., it is necessary to keep the contact wire geometry within defined limits.

Ex. 3. Complete the sentences using the words in brackets in the correct form. Pay attention to the constructions t h e … t h e … . - чем … , тем… .

Model: I like warm weather. The warmer the weather ____ I feel (good). → The warmer the weather, the better I feel.

1.I didn’t really like him when we first met.

But the more I got to know him, ____ like him. (much)

2.If you are in business you want to make a profit. The more goods you sell, _____ profit you get. (big)

3.It’s hard to concentrate when you are tired.

The more tired you are, it’s _____ to concentrate. (hard)

4.She had to wait a very long time.

The longer she waited, _____ she became. (impatient)

5.We don’t have much time left.

The sooner we leave, _____ we will arrive (early).

6.People learn easier when they are young. The younger you are, _____ you learn (fast).

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7.This hotel is very expensive.

______ the hotel, the better the service. (expensive) 8. You use too much electricity.

The more electricity you use, _____ the bill will be. (high)

9.The plan used to seem better.

The more I thought about the plan, ____ I liked it (little)

10.You are too lazy.

The more hardworking you are, ____ you will be. (successful)

Read the text and translate it using a dictionary if necessary.

O V E R H E A D L I N E S

The mechanics of power supply wiring is not as simple as it looks. Hanging a wire over the track, providing it with current and running trains under it is not that easy if it is to do the job properly and last long enough to justify the expense of installing it. The wire must be able to carry the current (several thousand amps), remain in line with the route, withstand wind (in Hong Kong typhoon winds can reach 200 km/h), extreme cold and heat and other hostile weather conditions.

Overhead catenary systems, called "catenary" from the curve formed by the supporting cable, have a complex geometry, nowadays usually designed by computer. The contact wire has to be held in tension horizontally and pulled laterally to negotiate curves in the track. The contact wire tension will be in the region of 2 tonnes. The wire length is usually between 1000 and 1500 metres long, depending on the temperature ranges. The wire is zigzagged relative to the centre line of the track to even the wear on the train's pantograph as it runs underneath.

The contact wire is grooved to allow a clip to be fixed on the top side. The clip is used to attach the dropper wire. The tension of the wire is maintained by weights suspended at each end of its length. Each length is overlapped by its neighbour to ensure a smooth passage for the "pan". Incorrect tension, combined with the wrong speed of a train, will cause the pantograph head to start bouncing. An electric arc occurs with each bounce and a pan and wire will soon both become worn through under such conditions.

More than one pantograph on a train can cause a similar problem when the leading pantograph head sets up a wave in the wire and the rear head can’t stay in contact. High speeds worsen the problem. The French TGV (High Speed Train) formation has a power car at each end of the train but only runs with one pantograph raised under the high speed 25 kV AC lines. The rear car is supplied through a 25 kV cable running the length of the train. This would be prohibited in Britain due to the inflexible safety approach there.

A waving wire will cause another problem. It can cause the dropper wires, from which the contact wire is hung, to "kink" and form little loops. The contact wire then becomes too high and aggravates the poor contact.

Overhead lines are normally fed in sections like 3rd rail systems, but AC overhead sections are usually much longer. Each subsection is isolated from its neighbour by a section insulator in the overhead contact. The subsections can be joined through special high speed section switches.

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To reduce the arcing at a neutral section in the overhead catenary, some systems use track magnets to automatically switch off the power on the train on the approach to the neutral section. A second set of magnets restores the power immediately

Various forms of catenary suspension are used, depending on the system, its age, its location and the speed of trains using it. Broadly speaking, the higher speeds, the more complex the "stitching", although a simple catenary will usually suffice if the support posts are close enough together on a high speed route. Modern installations often use the simple catenary, slightly sagged to provide a good contact. It has been found to perform well at speeds up to 125 m/hr (200 km/hr).

At the other end of the scale, a tram depot may have just a single wire hung directly from insulated supports. As a pantograph passes along it, the wire can be seen to rise and fall. This is all that is necessary in a slow speed depot environment. Trolley poles were used for current collection on low speed overhead systems and were common on trams or streetcars but they are now obsolete.

DC overhead wires are usually thicker and, in extreme load cases, double wires are used, as in Hong Kong Mass Transit’s 1500 v DC supply system. Up to 3000 volts overhead is used by DC main line systems (e.g. parts of France, Belgium and Italy) but below 1500 volts, a third rail can be used. In operating terms, the third rail is awkward because of the greater risk of it being touched at ground level. It also means that, if trains are stopped and have to be evacuated, the current has to be turned off before passengers can be allowed to wander the track. Third rail routes need special protection to be completely safe. On the other hand, some people consider the overhead catenary system a visual intrusion. Singapore, for example, has banned its use outside of tunnels.

On lines equipped with AC overhead wires, special precautions are taken to reduce interference in communications cables. If a communications cable is laid alongside rails carrying the return current of the overhead line supply, it can have unequal voltages induced in it. Over long distances the unequal voltages can represent a safety hazard. To overcome this problem, booster transformers are provided. These are positioned on masts at intervals along the route. They are connected to the feeder station by a return conductor cable hung from the masts so that it is roughly the same distance from the track as the overhead line. The return conductor is connected to the running rail at intervals to parallel the return cable and rails. The effect of this arrangement is to reduce the noise levels in the communications cable and ensure the voltages remain at a safe level.

Ex. 4. Go back to the text and translate the following phrases into Russian:

power supply wiring, justify the expense of installing, contact wire tension, to even the wear, worsen the problem, inflexible safety approach, slightly sagged, slow speed depot environment, visual intrusion, to reduce interference in communications cables, roughly the same distance.

Ex. 5. Go to the text and translate the following word combinations from Russian into English:

служит достаточно долго, выдерживать порывы ветра, следует держать напряженным, ухудшать ситуацию, ходовые рельсы, уменьшить возможность образования электрической дуги, опасность травмирования.

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