The video shows TBM Mom Chung breaking into the water-filled retrieval shaft last June. The water is drained from the shaft for the arrival of TBM Big Alma. The departure of the machines comes next as workers remove both TBMs, piece by piece, over several months. The retrieval shaft site was restored and vacated in January 2015.
This video was created by: http://www.centralsubwayblog.com/blog/2015/02/tunnel-boring-machines-disassembly/