On Jan 26, 9:30*am, wrote:

You'd have enough trouble just getting men with
shovels down those tiny tunnels never mind any construction machinery.


The running tunnel is 9 ft diameter : the running tunnel between
stations are all double track.

9 ft is a good deal larger that many site construction tunnel or even
final tunnels e.g. sewer or water tunnels that have construction
railways in them.


--
Nick