Theme: unusual railways

THEME: RAILWAY ELECTRIFICATION
(1) World railways are now busy in search of ways to increase their economic efficiency and the speeds of pas­senger and goods trains. One essential condition to achieve this is electric traction.
(2) The first attempt to apply electricity to transport purposes was made by Jacobi, a Russian physicist and electrical engineer. In 1838 he ran an electric boat at a speed of about 5 kph on the Neva river.
(3) Another major success in using electric power was made by Werner von Siemens who was the first to pro­duce a passenger electric locomotive. His locomotive was demonstrated at the ,exhibition in Berlin in 1879, It was a miniature four-wheeled loco hauling up to thirty passen­gers at a time round a narrow-gauged track 275 m long. The locomotive was so small that the (driver straddled it like a horse. But it was a practical locomotive which was furnished with power from the third rail placed in the track between the two running rails.¹
4) Two years later, a small electric railway, the first one in the world, was put into operation in Berlin. This line was soon followed by an electrically-operated railway brought into use in the British Isles. It was an under­ground railway in London opened to traffic in 1890.
(5) The Soviet engineers always took interest in rail­way electrification. As is known, it was V. I. Lenin who put forward the idea of the country's electrification. To realize this idea 200 outstanding Russian scientists, engi­neers and economists set to work. As a result, the GOELRO Plan was worked out in 1920. According to the plan the first railways to be electrified' were the ones carrying both heavy freight and passenger traffic as well as the subur­ban railways near big cities, such as Moscow, Leningrad and Kiev, с Since that time railway electrification ad­vanced rapidly.
(6) The world's longest Moscow—Lake Baikal electric railway put into service in 1961. Now the Soviet Union has about a quarter of the whole electrified net­work in the world.
(7) In spite of having a relatively short history elec­tric traction has made a remarkable progress. Now, one can say that electric railways perform valuable service on every continent.
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(8) When we study the geographical location of the routes over which electric traction is employed, we see, first of all, that the suburban railway routes of big cities with their dense and constant traffic are operated by elec­tric trains. We see, again, that the heavily-used trunk lines are most efficiently operated by electricity. Further, rail­ways in mountainous country, with heavy gradients,² are among the earliest to be converted to electric haulage.
(9) The chief attractions of electric haulage are four in number. One is great rapidity of acceleration. The next advantage is that the electric locomotive is always ready for use and can remain¹ in Service for practically the whole of, twenty-four hours continuously. It follows that under electrification the maintenance and operation costs are rel­atively cheap. Yet another essential benefit to be obtained is the ability of electrics to haul very long and heavy trains for there is practically no limit to the energy to be taken by the locomotive from the catenary. Besides, of all the existing kinds of traction it is the electric haulage that is most promising as regards speeds.
(10) The electric rolling stock is of two types, namely, locomotive-hauled trains and multiple-unit (m-u) trains, the latter being composed of motor coaches and trailers, that is, coaches without traction motors.
(11) Thanks to their rapid acceleration m-u trains are most suitable for suburban railways with their frequent stops and frequent services. As to electric locomotives they are mainly used to haul long-distance goods and passenger trains.
(12) Electric railways may use either direct or alternat­ing current. For the electric current to be fed to the trains the conductor rails or a system of overhead wires, often called the catenary, are needed. It is the power supply system that makes railway electrification a costly business since electric haulage makes it necessary for railways to be equipped with a whole system of electrical substations and cables to bring the power to the track. Because of a high construction cost railway electrification is justified on the railways with a high density of traffic. Thus the greater the density of traffic the more favourable situation for the operation of electric trains.
(13) There are some other drawbacks of electric haulage to be mentioned. For example, the electric trains cannot run anywhere beyond the lines equipped with the catenary. Besides, any serious breakdown in the power supply system can bring a large number of trains to a stand. In hard winter conditions the icing of the overhead wire or the conductor rail causes many troubles on electrified lines.
(1) Jahon temir yo'llari hozirgi vaqtda iqtisodiy samaradorligini va yo'lovchi va yuk poyezdlari tezligini oshirish yo'llarini izlash bilan band. Bunga erishishning muhim shartlaridan biri elektr tortishdir.
(2) Elektr energiyasini transport maqsadlarida qo'llashga birinchi urinish rossiyalik fizik va elektrotexnika muhandisi Yakobi tomonidan qilingan. 1838 yilda u Neva daryosida soatiga 5 km tezlikda elektr qayig'ini boshqargan.
(3) Elektr energiyasidan foydalanishda yana bir katta muvaffaqiyatga birinchi bo'lib yo'lovchi elektrovozini ishlab chiqargan Verner fon Simens erishdi. Uning lokomotivi 1879 yilda Berlindagi ko'rgazmada namoyish etildi, u uzunligi 275 m bo'lgan tor o'lchovli yo'l bo'ylab bir vaqtning o'zida o'ttiz nafargacha yo'lovchini tashiydigan miniatyura to'rt g'ildirakli lokomotiv edi. Lokomotiv shunchalik kichkina ediki, (mashinist uni otga o'xshab bosib o'tdi. Lekin bu amaliy lokomotiv bo'lib, u ikki harakatlanuvchi relslar orasidagi yo'lga o'rnatilgan uchinchi relsdan quvvat oladi.1).
4) Ikki yildan so'ng Berlinda dunyoda birinchi bo'lgan kichik elektr temir yo'l ishga tushirildi. Tez orada bu liniyadan keyin Britaniya orollarida elektr bilan boshqariladigan temir yo'l ishga tushirildi. Bu 1890 yilda Londonda qatnov uchun ochilgan er osti temir yo'li edi.
(5) Sovet muhandislari har doim temir yo'llarni elektrlashtirishga qiziqish bildirgan. Ma'lumki, mamlakatni elektrlashtirish g'oyasini ilgari surgan V. I. Lenin edi. Ushbu g'oyani amalga oshirish uchun 200 ga yaqin rus olimlari, muhandislari va iqtisodchilari ishga kirishdilar. Natijada, 1920 yilda GOELRO rejasi ishlab chiqildi. Rejaga ko'ra, birinchi navbatda og'ir yuk va yo'lovchi tashuvchi temir yo'llar, shuningdek, Moskva kabi yirik shaharlar yaqinidagi shahar atrofi temir yo'llari elektrlashtirildi. Leningrad va Kiev, s O'shandan beri temir yo'llarni elektrlashtirish tez sur'atlar bilan rivojlandi.
(6) Dunyodagi eng uzun Moskva - Baykal ko'li elektr temir yo'li 1961 yilda foydalanishga topshirilgan. Hozirda Sovet Ittifoqi dunyodagi butun elektr tarmog'ining chorak qismiga to'g'ri keladi.
(7) Nisbatan qisqa tarixga ega bo'lishiga qaramay, elektr tortish ajoyib muvaffaqiyatga erishdi. Endi aytish mumkinki, elektr temir yo'llari har bir qit'ada qimmatli xizmat ko'rsatadi.
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(8) Elektr tortish quvvati qo'llaniladigan marshrutlarning geografik o'rnini o'rganar ekanmiz, birinchi navbatda, zich va doimiy harakatga ega bo'lgan yirik shaharlarning shahar atrofidagi temir yo'l yo'nalishlarida elektr poyezdlari harakatlanishini ko'ramiz. Biz yana ko'ramizki, ko'p foydalaniladigan magistral liniyalar elektr energiyasi bilan eng samarali ishlaydi. Bundan tashqari, tog'li o'lkada temir yo'llar og'ir gradyanli2 bo'lib, elektr transportiga o'tkazilgan eng birinchilardandir.
(9) Elektr transportining asosiy diqqatga sazovor joylari to'rtta. Ulardan biri tezlashuvning katta tezligi. Keyingi afzallik shundaki, elektrovoz har doim foydalanishga tayyor va deyarli butun yigirma to'rt soat uzluksiz xizmat ko'rsatishda qolishi mumkin. Bundan kelib chiqadiki, elektrlashtirish sharoitida texnik xizmat ko'rsatish va foydalanish xarajatlari nisbatan arzon. Yana bir muhim afzallik - bu elektrning juda uzoq va og'ir poezdlarni tashish qobiliyatidir, chunki lokomotiv tomonidan katenardan olinadigan energiya deyarli cheklanmagan. Bundan tashqari, barcha mavjud tortish turlaridan tezlik bo'yicha elektr transporti eng istiqbolli hisoblanadi.
(10) Elektr harakat tarkibi ikki xil, ya'ni lokomotivli poezdlar va ko'p agregatli (m-u) poezdlar, ikkinchisi avtovagonlar va tirkamalar, ya'ni tortish motorlari bo'lmagan vagonlardan iborat.
(11) Tez tezlashishi tufayli m-u poezdlar tez-tez to'xtab turishi va tez-tez qatnovi bilan shahar atrofi temir yo'llari uchun eng mos keladi. Elektrovozlarga kelsak, ular asosan uzoq masofalarga yuk va yo'lovchi poezdlarini tashish uchun ishlatiladi.
(12) Elektr temir yo'llari to'g'ridan-to'g'ri yoki o'zgaruvchan tokdan foydalanishi mumkin. Poezdlarga elektr tokini etkazib berish uchun o'tkazgich relslari yoki ko'pincha katenar deb ataladigan havo simlari tizimi kerak. Aynan elektr ta'minoti tizimi temir yo'lni elektrlashtirishni qimmatga tushadigan biznesga aylantiradi, chunki elektr transporti temir yo'llarni elektr nimstansiyalari va kabellarning butun tizimi bilan jihozlashni talab qiladi. Qurilish qimmatligi tufayli temir yo'lni elektrlashtirish yuk tashish zichligi yuqori bo'lgan temir yo'llarda oqlanadi. Shunday qilib, harakat zichligi qanchalik ko'p bo'lsa, elektr poezdlarining ishlashi uchun qulayroq sharoit mavjud.
(13) Elektr transportining boshqa kamchiliklari ham bor. Masalan, elektr poyezdlari katenar bilan jihozlangan liniyalardan tashqari hech qanday joyga yura olmaydi. Bundan tashqari, elektr ta'minoti tizimidagi har qanday jiddiy buzilish ko'plab poezdlarni stendga olib kelishi mumkin. Qattiq qish sharoitida havo simi yoki o'tkazgich relslarining muzlashi elektrlashtirilgan liniyalarda ko'plab muammolarni keltirib chiqaradi.