"A petition for single-sex spaces on the Tube has prompted outrage, yet versions abroad have long proved their worth
In recent years, female-only train travel has become a norm in multiple countries."
It is studiously avoided what changed to require the single-sex spaces!
You can figure it out, though.
"“In cultures where, sadly, women are viewed as second-class citizens and treated as such, the women-only carriage provides a safe space for women to travel around and live an independent life, and it often enables them to have better opportunities,” says Lallie Fraser, a regular visitor to India, who admits she has experienced unwanted male advances on busy Delhi trains in the past."
https://archive.ph/uLRLm