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A wrong side failure describes a failure condition in a piece of railway signalling equipment that results in an unsafe state. A typical example would be a signal showing a 'proceed' aspect (e.g. green) when it should be showing a 'stop' or 'danger' aspect, resulting in a "false clear". (The converse is a right side failure, where even with any reduction the resulting state is safe overall.) == Example of how a wrong side failure may occur == Consider a relay that has to energize to show a green light. If a wire breaks, or the battery is drained, then the relay will de-energize and the signal will show a red light, which is fail-safe. If a stray wire from another circuit touches the wire connected to that same relay, then that would be a wrong side failure, which is potentially dangerous. This stray wire can be guarded against by ensuring that the insulation on the relay wire is of good quality, and that all terminals are locked away. In addition, the relay may be double-switched, that is to say that it only energizes if a positive circuit and a negative circuit are both complete. That would then require two stray wires to cause a wrong side failure, which is much less likely than a single stray wire. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Wrong-side failure」の詳細全文を読む スポンサード リンク
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