What it meant in practical terms was that the giant tunnel boring machines were burrowing in close proximity to existing tunnels that were ferrying passengers just meters away. In order to precisely monitor the situation, hundreds of instruments and sensors were installed in the tunnels, looking at alignments of tracks and power transmissions in the other lines at service.
This, by the way, is at the Tanah Merah station platform on the East-West Line, which is above ground.
|camera||Canon EOS 7D Mark II|
|exposure mode||full manual|