The actual tunnel segment doesn't feel any different from a New York subway, except it's smooth and quiet.

The tunnel segment will have 13 underground stations.

Building the tunnel structure required the pre-casting of 5 tunnel segments and an open boat unit.

Most of the tunnel segments are shorter than four miles, for several reasons.

TFL says that it was caused by rainwater causing tunnel segments to expand.

It took an hour for me to get down to the hospital, three tunnel segments and five levels in the dropshaft.

In unstable, fractured ground, the thrust is shifted to thrust cylinders that push off against the tunnel segments behind the machine.

At the time of collapse, construction work on the tunnel segments had finished, and the backfilling operation was taking place.

We all share the work-extending the tunnel segments, farming, raising the children, whatever needs doing.

This can cause electrolytic damage and even arcing if the tunnel segments are not electrically bonded together.