Segregating 153s could be tricky :-) You would also need some way of
enforcing the rule. Would people be willing to sit in the luggage
racks on packed-to-the-roof trains, when there was plenty of space in
an adjacent women-only coach?

Statistically it may well be white males aged 18-24 that are most at risk
of
attack, but women tend to feel the most vulnerable using public transport
late at night. I would imagine such an idea would have to be enforced by
a
security guard travelling in the women-only carriage and the communication
door would have to be locked.

Not only are the vast majority of attacks on males, but females are more
likely to be attacked by other females. I think locking the communication
door would make most people feel more worried.

Bit like corridor stock. Nowhere to go if someone blocks one door.