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What with this shifting of the zero and the very slight rise and fall in the current produced by rapid signalling, the ordinary land line instruments are quite unserviceable for work upon long cables. 1952: By the end of 1952, TVs could be found in 20 million households across America, a rise of 33% from the previous year. It is an embarrassing nuisance only solved by being pushed onto the third rail by another train or by obtaining special long leads with a plug at one end for the train and shoes at the other end for the third rail. Woe betide the driver who stops his train with all the shoes "off juice" or "gapped". They are used when it is necessary to isolate a train with an electrical fault in its current collection system. As mentioned above, CBS’s color system only worked with a small number of TVs across America. Only 12 customers across America could see the first color TV broadcast.

Many installations seen today were first built more than 100 years ago, some when electric traction was barely out of its diapers, so to speak, and this has had a great influence on what is seen today. As AC is easier to transmit over long distances, it is an ideal medium for electric railways. Of course, as many railways use the running rails for signalling circuits as well, special precautions have to be taken to protect them from interference. On lines equipped with AC overhead wires, special precautions are taken to reduce interference in communications cables. 2005: Flat screen TVs and HDTVs are introduced for the first time. 2013: Netflix released its first original series, "House of Cards," marking a shift towards streaming services for original content. To introduce his apparatus for signalling on long submarine cables, Sir William Thomson entered into a partnership with Mr. C. F. Varley, who first applied condensers to sharpen the signals, and Professor Fleeming Jenkin, of Edinburgh University.

Professor Morse was appointed electrician to the company. Communications circuits provide voice and signal communications among equipment shelters and company offices. With telephone cables of moderate length these troubles would not be serious, and, if longer cables were necessary, metallic circuits could be used. It was difficult to handle the wires without abrading the gutta-percha; and, when safely laid, the gutta-percha was attacked by coal-gas, vegetable growths, and the constituents of the soil. This is one of the most common causes of wires "being down". The most common reason is when a shoe breaks off and its connecting lead to the electrical equipment on the train has to be secured safely. These were used for current collection on low speed overhead systems and were common on trams or streetcars but they are now obsolete. Tower sizes and footprints are dependent on cable technology choice, system capacity and tower span distances. Figure 10: Overhead line suspension system. The currents in the three phases of the transmission (or sub-transmission) line are never quite equal; if they are wye-connected, the MGN carries the residual unbalance current. In Europe, some locomotives are equipped to operate under four voltages - 25 kV AC, 15 kV AC, 3,000 V DC and 1,500 V DC.

The separations shown in this diagram are typical, although there are numerous exceptions and special cases. This diagram shows a DC 3-Rail Traction System with the location of the current rail in relation to the running rails. This prohibits further extension of the single-wire system under-ground, for technical reasons. Figure 4: 3rd rail current collection system on the New York Subway showing the third rail with a wooden cover fitted to reduce the effects of snow and ice. It also suffers during bad weather, the smallest amount of ice or snow rendering top contact third rail systems almost unworkable unless expensive remedies are carried out. Following are photos of a few representative examples. 1979: Some people believe it’s the "beginning of the end for TV" as a poll indicated that 44% of Americans were unhappy with current programming and 49% were watching TV less than what they did a few years earlier.

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