这条隧道最终将在伦敦地铁北线（NorthernLine）隧道上方1.5米处通过，在我的职业生涯里，这差不多是最小的间隔了。
The tunnel will eventually pass 1.5m above the Tube 's Northern Line . In my job , it doesn 't get much closer than that .
伦敦地铁北线