Upon the miasma of midnight, a darkling spirit identified as SB
gently breathed:

Bearing in
mind that there have been a number of fatal crashes in the US due to
the drivers texting, is this acceptable behaviour? SB.

Slight difference though, in the cases in the US, the driver was
actually driving the train. On the DLR, unless working in emergency
manual mode (where the train captain actually handles the power
controller thingie), it's all fully automated.

At the time the DLR was built, it was felt that the public wouldn't
accept totally automated, staffless trains. Hence the provision of the
train captains to be a staff presence on board without having to have
actual drivers.