Motive Power
Vehicles which provide motive power to haul trains include locomotives and motor coaches. Motive power is classified into:
self-sufficient units which generate their own power from fuel such as diesel locomotives, gas turbine locomotives, locotractors, diesel trains, turbotrains, railcars, and steam locomotives;
not self-sufficient units which take power from an outside source of electricity such as electric locomotives and electric trains.
Locomotives are subdivided in their usage in rail transport operations into:
mainline locomotives
goods (freight) locomotives,
passenger locomotives,
mixed traffic locomotives;
shunting locomotives/shunters;
locomotives for both line and shunting operations.
These categories determine the locomotive’s size, starting tractive effort and speed.
A number of diesel or electric units can be combined according to the power needed for a particular train with only one crew required for all the units.
Electric locomotives. Unlike diesel locomotives, which produce their own power, electric locomotives convert the electric power that is generated elsewhere.
Electric locomotives can be divided into those using alternating current (AC) and those using direct current (DC). They pick up current from an overhead wire. An electric locomotive consists of a mechanical part, electrical and pneumatic equipment. A mechanical part comprises a body, bogies, brake equipment, and coupling and drawgear. A body is usually of all-metal construction and contains electrical equipment. A body is supported on 2- or 3-axle bogies, and they, in turn, on wheel sets. Bogies are composed of frames with traction motors on them.
An electric locomotive has a number of advantages:
It can develop greater power compared to diesel locomotives.
It is cleaner and quieter in operation.
It requires little time in the shop for maintenance.
Its maintenance costs are low.
It has a longer life than diesels.
The greatest drawback of electrification is the high capital investment and maintenance cost of traction substations and overhead wires.
Electric trains. Electric trains are used for suburban and intercity passenger service on electrified lines. They are formed of 4, 6, 8, 10 or 12 motor coaches and trailers.
The term multiple unit or MU is used to describe self-propelled coaches (carriages, cars) coupled with other units and controlled from one driving cab. MU coaches can be motor units (motor coaches) or trailer units. Multiple units are classified by their power source and are of two main types: electric multiple unit (EMU) and diesel multiple unit (DMU).
Diesel locomotives. A diesel locomotive has its own power supply unit (usually a diesel engine). A diesel is an internal combustion engine with the efficiency of 40-42%. This engine drives the wheels by mechanical, hydraulic or electric transmission. Of the three, electric transmission is most popular.
A diesel locomotive has a number of advantages:
Being self-sufficient it is not connected with an overhead wire.
It can be operated in any climate.
It does not require costly catenary and traction substations.
A diesel locomotive has also a number of disadvantages:
It pollutes the environment.
It has a great number of friction parts.
It requires the delivery of fuel and lubricants.
The run is limited in terms of fuel provision.
There is a fire risk.
A diesel engine produces a lot of noise.
The diesel locomotives excel in shunting where intensity of use is high.
Diesel trains. A diesel train is formed of motor coaches and three or more trailers used to transport passengers on non-electrified sections.
Railcars. A single self-propelled carriage is called a railcar.
Locotractors. A locotractor is a locomotive with a 150 kW carburetor engine.
Gas turbine locomotives. A gas turbine locomotive is a locomotive that uses a gas turbine to drive an electrical generator or alternator. The electric current thus produced is used to power traction motors. After the 1973 oil crisis and the subsequent rise in fuel costs, gas turbine locomotives became uneconomical to operate, and many were taken out of service.
Exercise 2. Choose the correct word.
1) A diesel locomotive has __________ advantages _________ disadvantages.
a) either ... or, b) neither ... nor, c) both ... and
2) A _________ locomotive is now rare.
a) diesel, b) electric, c) gas-turbine
3) ________ is particular suitable for switching services.
a) diesel traction b) electric traction c) steam traction
4) The use of two-unit diesels provides _________.
a) greater cleanliness b) higher power c) less damage to the track
5) Because high horsepower is required for high-speed operation, the diesel is _________ the electric for high-speed passenger services.
a) less desirable than b) more desirable than c) as desirable as
6) A trailer is a passenger vehicle in a multiple unit train which ________traction power equipment.
a) has, b) has no, c) has a lot of
7) ________ transmission is by far the most common.
a) Electrical, b) Mechanical, c) Hydraulic
8) The high capital costs required for substations and electrical-distribution networks ________the electrification of all railroads.
a) have hindered (препятствовать), b) have stimulated, c) have provided
Exercise 3. Find synonyms in the text to the following English words.
1) energy |
6) EMU |
2) drawback |
7) DMU |
3) to draw trains |
8) DC |
4) to produce power |
9) AC |
5) 6-wheeled bogie |
10) GTEL |
Exercise 4. Find English equivalents in the text to the following Russian words and phrases in the text.
1) подразделяются на |
7) тяговые подстанции |
2) вырабатывают энергию |
8) источник питания |
3) по роду работы |
9) двигатель внутреннего сгорания |
4) в любых климатических условиях |
10) ряд недостатков |
5) более продолжительный срок службы |
11) ограничен пробег по запасу топлива |
6) большие капиталовложения |
12) вывести из эксплуатации |
|
13) неэлектрифицированные участки |
Exercise 5. Translate this paragraph about a switcher into British English.
A switcher is a small railroad locomotive intended not for moving trains over long distances but rather for assembling trains ready for a road locomotive to take over, disassembling a train that has been brought in, and generally moving railroad cars around – a process usually known as switching. They do this in classification yards.
Exercise 6. Decide if the sentences are true or false.
1) The diesel locomotive is a self-sufficient unit.
2) Electric trains and locomotives are capable of higher performance and lower operational costs than diesel power.
3) Diesel-electric locomotives, because they tend to be less technically complex than electric locomotives, are both easier and cheaper to maintain and have extremely long working lives.
4) It is not necessary for every single coach in an MU set to be motorized.
5) The capital cost of electrifying track is not high.
6) A motor coach is a powered rail vehicle able to pull several trailers and at the same time transport passengers or luggage.
7) Electric locomotives differ from steam and diesel ones being simply power-converting, rather than power-generating, devices.
8) Diesel traction can be used on the lines where the traffic is sufficiently dense (интенсивный) and high capital investment can be repaid.
Exercise 7. Explain the following statements. Work in pairs.
The electric traction is desirable for high-speed passenger services.
The diesel locomotives excel in railroad switching.
Exercise 8. Translate the following texts into Russian. Use a dictionary. Then compare your translation with a partner to improve.
1.