What is a Third Rail?
A third rail is an electric rail installed in subway and some light rail systems to provide power to electric trains. Many subway systems use third rails because they are cheap to install and they run relatively efficiently, although there are safety problems associated with them. Many consumers who use subway systems are familiar with the dangers of the third rail, since they are usually clearly marked. These well publicized dangers have led to the use of “third rail” as a slang term, in reference to a political issue which is so charged that it is essentially untouchable.
Early subway systems used combustion to power their trains. This generated a great deal of pollution, making the air difficult and unpleasant to breathe. Many switched to electricity as soon as it became available, because it was so much cleaner. There are a number of ways to provide electricity to am electric railway, including using overhead wires and installing a third rail.
The third rail lies on the ground, next to the tracks used by the train. Depending on the system, the third rail may be located to one side, or it may be in the middle of the tracks. A paddle extends from the train to come into contact with the third rail, conducting electricity on to the train to power it. Numerous trains can use the system at once, disengaging when they no longer require power.
The clearest disadvantage to the third rail is that it can be very dangerous. It constantly carries a very high electrical current, which can be fatal to animals and humans which come into contact with it. Many safety systems are aimed at preventing contact with the third rail, ranging from sheaths which make physical contact difficult to high platforms and guard rails meant to make it more difficult to get onto the tracks.
However, in areas where tracks are level with the ground, there have been incidences of severe injury and death as a result of contact with the third rail. On standard elevated and underground tracks, the third rail is usually located on the side of the tracks opposite to emergency tunnels and stairways, to ensure that people will not come into contact with the third rail if they need to evacuate the train. In stations, the third rail is located against the wall of the station, rather than on the platform side, so that people who fall onto the tracks will be in less danger.
Written by S.E. Smith
