Text b AC or DC traction

EXERCISES

 

Ex. 10  Form adverbs from adjectives with the help of suffix «-ly» and translate them:

a) simple, ideal, usual, considerable, certain, easy; b) main, close, new, near, most, great.

 

Ex. 11 Pay attention to the translation of the words «its» and «their»:

a) the motor and its functions; electrical transmission and its advantages; the electrical loco and its speed; b) motors and their operation; new methods and their application; substations and their operation.

 

Ex. 12       Translate the attributive groups:

1)    the cab control system device improvement program;

2)    AC or DC passenger train system choice;

3)    the dual-voltage (25kV-50Hz-3kV-DC)train;

4)    the 654 km Moscow — St Petersburg main line;

5)    the 1520 mm gauge six — car passenger train.

 

 

Ex. 13 Translate the sentences paying attention to the translation of the word «means»:

1.    Our University is called the University of Means of Communications.

2.    Locomotive is one of the constantly developing means of transport.

3.    When speaking about pantograph we must know what the word «shoe» means.

4.    It is easy to boost the AC voltage which means that more power can be sent over the transmission lines with DC.

5.    There are different means of protecting catenary from corrosion.

6.    By means of increasing the number of trains on the same line it is

possible to carry more passengers and freight.

 

Ex. 14  Pay attention to the translation of the words «number, the number of, a number of»:

1.    Direct current has been used on a number of mainline systems in

some countries of Europe.

2.    The number of electrified railways will increase in Russia by 2005.

3.    The St. Petersburg — Moscow train «Smena» is train number 25.

4.    A number of students will work as car attendants this summer.

5.    The cars of a passenger train are always numbered.

 

Ex. 15  Define the function of the «-ing-form» and translate the sentences into Russian:

1.    While testing the new locomotive both the driver and the engineer noticed malfunctioning of the motor.

2.    After testing, the motor was removed and sent back to the manufacturer.

3.    The Japanese Railways started testing new locos for the famous Shinkansen.

4.    The experimental train developed a very high speed, the engineer testing the work of the control system devices in the cab.

 

Ex. 16 Read and translate the text:

Traditional training for train drivers is expensive both in terms of cost and time. Currently, in 2003, it costs 40,000 English pounds to provide basic training for one driver and takes up to 11 months.

Theoretical training is easy to organize and typically one instructor can cope with up to 12 trainees (ученики). But train drivers require considerable practical instruction to acquire the necessary skills which drivers need for competent performance. Practical training requires minimum 300 hours on service trains with an instructor. Such training provides experience of normal everyday driving duties. However, it is almost impossible to provide experience of unusual and emergency situations.

Most practical training is carried out initially in a depot using old rolling stock to provide training in shunting and mainline driving. It is in this area of training that simulation can be most effectively used.

There are many problems that require attention of both railway managers and trainers if simulation is to be successfully introduced into an existing training system.

 

(International Railway Journal, 2001.)

Ex. 17 Suggest a headline for the text.

Ex. 18 Compare the systems of driver training in Great Britain and in Russia.

 

 

AC OR DC TRACTION

There are AC and DC motors, and either of them can work with an AC and DC supply. You just need to use the right sort of a control system between the supply and the motor and it will work. However, the choice of AC or DC power transmission system is important. Generally, it's a question of what sort of railway you have. It can be summarised simply as AC for long distance and DC for short distance. But, of course, there are exceptions.

It is easier to boost the voltage of AC than that of DC, so it is easier to send more power over transmission lines with AC. This is why national electrical supplies are distributed at up to 765,000 volts AC. As AC is easier to transmit over long distances, it is an ideal medium for electric railways. Only the problems of converting it on the train to run DC motors restricted its widespread adoption until the 1960s.

DC, on the other hand, was the preferred option for shorter lines, systems and tramways. However, it was also used on a number of main line railway systems, and still is in some parts of continental Europe. Apart from requiring a simple control system for motors, the smaller size of urban operations meant that trains were usually lighter and needed less power. Of course, it needed a heavier transmission medium, a third rail or a thick wire, to carry the power and it lost a certain amount of voltage as the distance between the supply connections increased. This was overcome by placing substations at close intervals — every three or four kilometres at first, nowadays every two or three kilometres on a 750 volt system — compared with every 20 kilometres or so for a 25 kV AC line.