Paul Scott wrote:
It is because the Central line has full automatic train operation (ATO),
which for normal day to day use drives the trains nearer the limits than

It can't be just that surely. Even on the long open stretches outside
where the drivers could give it some welly the northern trains still
chug along at a leisurely pace and take their time getting to it.
Perhaps the whole line has a low linespeed now, dunno.

B2003