Engineers from Newcastle have been developing blast-resilient train carriages to minimise the impact that a terror attack might have to the public and emergency services.
Preventing flying objects is the key.
Tethering ceiling panels reduced the risk of fatalities and injury from flying shrapnel and also meant the gangways were kept relatively clear of debris, allowing emergency staff quick access to the injured.
More top news
It will be increasingly humid and thundery with highs of 30C or more today.
Holidaymakers in Tunisia are determined not to be beaten. But, as Neil Connery writes, it won't be easy to escape the shock of the massacre.
Drink lots of water, stay out of the sun during the middle of the day, and take particular care of vulnerable people.