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| Re: Fourth Rails and Safety (832312) | |||
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Re: Fourth Rails and Safety |
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Posted by Subterranean Railway on Sat Sep 12 02:44:17 2009, in response to Re: Fourth Rails and Safety, posted by Bill West on Fri Sep 11 21:53:29 2009. The center rail does not merely exist as a current return path grounded in strategic places to alleviate electrolysis of neighboring infrastructure; it's actually energized at approximately -210 volts in conjunction with the ~420 volt side rail. A reference point is established by bridging the two current-carrying rails with a voltage divider tapped to ground.Sort of like asking would being hit in the head at 30mph by a metal cover over the coupler be safer than being hit directly by the coupler. WADR, this is a very poor analogy. Merely being on a traditionally-electrified system's roadbed is far from certain death. Being on the roadbed is extremely risky no matter how you rate the individual hazards so I doubt if anyone cares about the extra power rail. Countless people fall into roadbeds; I've witnessed a couple accidents firsthand (and I'm not an especially frequent mass transit rider). I've even helped a woman who was unable to climb back up to the platform by herself. Neither of these people would have been so fortunate in a LU-esque electrified system, as both ended up in the trough after their falls. Unless a person is disoriented, the principal danger of being in a traditionally-electrified system's roadbed is an oncoming train, which, while certainly considerable, is relatively easily avoided.1 It seems a far graver danger exists in the LU, where merely falling on the roadbed in the absence of trains can quite easily kill. 1: Except in stations where the third rail lies underneath the platform edge, in which falling on the third rail poses a real danger. |
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