The contractor shall retighten the nuts one week after joint installation and a second time just before final lining and leveling of the track.

承包商应于接头安装后一周重新拧紧螺母，并就在轨道最终衬砌和整平前再一次拧紧。

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There are three components to this system: a large electrical power source, metal coils lining a guide way or track, and large guidance magnets attached to the underside of the train.

这种系统有三个组成部份：一个大电源、一条导向线路或轨道沿线的金属线圈、以及附加在列车下面的大导向电磁铁。

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Insulated joints if required shall be installed just before final leveling and lining of the track.

需要时，绝缘接头应在轨道最终衬砌和整平前安装。

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The Rail Accident Investigation Branch (RAIB) said the broken sections were part of an auger drill that had "penetrated the tunnel lining before falling on to the track".

BBC: Construction drill came from site above rail tunnel