Pyromancer wrote:

Is all red-zone track work on DLR lines forbidden while they are
operating, or is there a facility for a train captain to take manual
control if passing a work site, and the train to stop if he/she doesn't?

The latter - in 1996 following the Docklands bomb DLR trains ran on manual
over the section of track for a while, with the onboard guard taking the
controls (they're in the box at the front of the train).