▁Vi ad uct ▁replacement ▁tunnel ▁project ▁in ▁ ▁Seattle . ▁It ▁was ▁made ▁by ▁Hit achi ▁Z osen ▁Sak ai ▁Works ▁in ▁Os aka , ▁Japan , ▁and ▁the ▁machine ' s ▁assembly ▁was ▁completed ▁in ▁Seattle ▁in ▁June ▁ 2 0 1 3 . ▁T unnel ▁b oring ▁began ▁on ▁July ▁ 3 0 , ▁ 2 0 1 3 , ▁with ▁the ▁machine ▁originally ▁scheduled ▁to ▁complete ▁the ▁tunnel ▁in ▁December ▁ 2 0 1 5 . ▁ ▁On ▁December ▁ 6 , ▁ 2 0 1 3 , ▁work ▁was ▁halt ed ▁approximately ▁ ▁into ▁the ▁planned ▁ ▁route ▁because ▁of ▁an ▁unexpected ▁imped iment . ▁Initial ly , ▁it ▁was ▁thought ▁that ▁the ▁machine ▁had ▁dam aged ▁several ▁of ▁its ▁cutting ▁bl ades ▁after ▁encounter ing ▁a ▁steel ▁pipe ▁that ▁was ▁used ▁to ▁measure ▁ground water ▁in ▁ 2 0 0 2 ▁around ▁the ▁Al ask an ▁Way ▁Vi ad uct . ▁However , ▁subsequent ▁investig ations ▁revealed ▁that ▁port ions ▁of ▁the ▁main ▁bearing ▁se al ▁system ▁were ▁dam aged , ▁which ▁caused ▁the ▁bearing ▁to ▁over he at ▁during ▁operation . ▁Over ▁the ▁next ▁two ▁years , ▁a ▁recovery ▁pit ▁was ▁d ug ▁from ▁the ▁surface ▁in ▁order ▁to ▁access ▁and ▁lift ▁the ▁machine ' s ▁cut ter head ▁for ▁repair ▁and ▁partial ▁replacement ▁in ▁ 2 0 1 5 . ▁ ▁Ber tha ▁res umed ▁tunnel ▁b oring ▁on ▁December ▁ 2 2 , ▁ 2 0 1 5 , ▁but ▁was ▁stopped ▁in ▁early ▁January