D7666 wrote:

On Mar 15, 10:53*am, Mizter T wrote:

Tunnel boring


So, it's finally really happening.


Most days I travel one way or the other through Paddington on the
Hamcity & Mersmith line and I've been watching the machinery being
assembled bit by bit. Its impressive kit. I don't recall the channel
tunnel machinery being as impressive but maybe grey cells are
decaying.


The Channel Tunnel machinery was crude and simplistic on the British
side, but extremely sophisticated and impressive on the French side.

The British tunnelling engineers laughed at the French machines,
claiming that they were absurdly complex and would make very slow
progress compared to the much simpler machines on the British side.

In the final reckoning, the French machines were very reliable and
worked faster than expected despite encountering ground conditions
that were much worse than expected. Meanwhile, the British machines
struggled in better ground that the French had to deal with and proved
unreliable and inadequate.

The planned meeting point between the British and French tunnel drives
had to be moved towards Kent several times (and by significant
distances) because the French machines made such rapid progress
compared to ours.