1. Ticket barriers at every station
2. Security guards / police patrols for stations and trains
3. A women-only carriage for late-night services.

Aren't (young-) men more at risk than women? I know there is a widely
held view that if an 18 year old female is attacked it is a serious
crime, but if an 18 year old male is attacked "he needs to learn to
look after himself", but in terms of actual violent assaults I'm sure
I've read that males are more at risk.

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?

Perhaps if properly calculated you could have people getting off at
different stops in different (locked) carriages, perhaps stations with
the same fare could have the same carriage if there are more stations
than coaches, or the complete opposite if there are ticket checks at
the higher priced station.


This would work especially well along routes from a medium or large
station through small unmanned stations.
For example:

Middle of the night service from station X which is relatively
abandoned so has no ticket gates in use.

Guard, Driver and any station staff could check tickets at the train
and advise which coach to sit in.

At the relative station the doors of that coach are unlocked and the
passangers can alight (with further ticket checks if necessary)