How do they get trains into the london underground?

Question

is it true trains are sometimes put in by digging up roads and lowering them in?

Answer 1

It's not true!  All subway systems, everywhere in the world have their yards above ground and the rails in that system connect to regular surface rails ... somewhere in their system.  When a new car is delivered to a subway system, it's delivered in a regular surface train to the system that ordered it, it gets switched on the that system's tracks and can be put into service.

Answer 2

they have a work and marshalling yard above ground ,this is were they enter the underground

Answer 3

GO TO CHINA

Answer 4

no - sections of the tube are overground, it isn't completely enclosed in tunnels.