It should be feasible to run it 24hrs during weekends only. Stockholm's subway does this and is closed normally at night weekdays. The headways are long enough

It should be feasible to run it 24hrs during weekends only. Stockholm's subway does this and is closed normally at night weekdays. The headways are long enough (30+ minutes out on the branches) that repairs can be carried out if need be by switching to the other track (not sure if they actually do this regularly).