Officers who police Scotland's railways are to carry Tasers as part of a security step-up on the network.
British Transport Police (BTP) said the decision to equip a number of specially-trained officers with the device is a "proportionate" response to the current terrorist threat to the UK.
The force cited an incident at Leytonstone station in east London in December where police used a Taser on a man who slashed a stranger, stopping him from harming further passengers.
Temporary Assistant Chief Constable Alun Thomas said:
Chief Superintendent John McBride, divisional commander for Scotland, said: