 In Phase 1 , there was tunneling between East 63rd and 92nd Streets and a 248 @-@ by @-@ 23 @-@ meter @-@ wide ( 814 by 75 ft ) TBM launch box was built . That tunnel box is now part of the 96th Street station . Two access shafts were constructed for the 72nd Street station . <unk> or diaphragm walls , 1 @.@ 1 meters ( 3 @.@ 6 ft ) wide and 6 @.@ 1 meters ( 20 ft ) long and about 35 meters ( 115 ft ) deep , were built alongside the sections between East 93rd and 95th Streets . Since the rock is shallower between East 91st and 93rd Streets , 1 @.@ 1 @-@ meter @-@ diameter ( 3 @.@ 6 ft ) secant piles did the same work at shallower depths . 
