Catenary Suspension Systems

230. Various forms of catenary suspension are used, depending on the system, its age, its location and the speed of trains using it. A simple catenary, slightly sagged to provide a good contact, is often used. It works well at speeds up to 125 m/hr (200 km/hr).The higher is the speed, the more complex is the catenary.

231. DC overhead wires are usually thicker and, in extreme load cases, double wires are used. Up to 3000 volts overhead line is used by DC main line systems.

232.

Vocabulary

234. catenary [kə'tJnqrI] контактный провод

235. dropper wire струна контактного провода

236. route [rHt] ж.-д. магистраль

237. bouncing подпрыгивание

238. hostile ['hOstaIl] враждебный

239. tension ['tenSqn] натяжение

240. laterally ['lxtqrqlI] в сторону, вбок

241. grooved [grHvd] с желобком, с канавкой

242. clip [klIp] зажим

243. pantograph ['pxntqgrRf] пантограф

244. contact strip контактная вставка

245. worn through изношенный

246. even [Jvn] равномерный; ровный

247. stitched catenary контактный провод с рессорной струной

248. compound catenary сложная подвеска контактного провода

249. running conditions условия эксплуатации

250. horns рога

251. break off отламывать(ся)

252. to hook over зацепиться

253. piston ['pIstqn] поршень

254. transverse [trxns'vWs] поперечный

255. sagged провисший

256. support arm кронштейн

257. bring down свалить; сломать

258.

259. Exercise 4. Read the text. Translate it from English into Russian.

260.

Pantographs

262. Current is collected from overhead lines by pantographs. Pantographs are easy in terms of isolation - you just lower the pantograph to lose the power supply to the vehicle. Since the pantograph is usually the single point power contact for the locomotive, it must maintain good contact under all running conditions. The higher the speed, the more difficult the maintenance of good contact. There exists the problem of a wave being formed in the wire by a pantograph moving at high speed.

263. Pantograph contact is maintained either by spring or air pressure. Compressed air pressure is better for high speed operation. The pantograph is connected to a piston in a cylinder and air pressure in the cylinder holds the pantograph in the raised condition.

264. The contact strips of the pantograph are supported by a lightweight transverse frame which has "horns" at each end. They are turned downwards to reduce the risk of the pantograph being hooked over the top of the contact wire. A train moving at speed with its pantograph hooked over the wire can bring down several kilometres of line before it is detected and the train stopped. The most sophisticated pantographs have horns which are designed to break off when struck hard, for example, by a dropper or catenary support arm. These special horns have a small air pressure tube attached, which, if the pressure is lost, will cause the pantograph to lower automatically and so reduce the possible wire damage.

265.

Грамматика

266.

Предлоги

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