From Friday 22 British Transport Police special officers will be armed with the devices to assist them in keeping the public, rail staff and themselves safe, the service said.
The rollout comes as the force responds to risks around terrorism, public safety and public order offences on the railway.
It said the first wave of specials all successfully completed a three-day training course on how to use the device alongside fully fledged constables.
British Transport Police's Specials Chief Officer, Ben Clifford, said: “I’m delighted that we are able to be the first force in the country to operationally deploy specials equipped with Taser. Our specials are exposed to the exact same risks as regular officers and are a vital part of our frontline workforce.
“Allowing them to carry the device is a positive step both in recognising the skills and competence of our part-time, volunteer officers and further strengthens our commitment to ensuring the railway is a safe environment for passengers and rail workers.
“We regularly deal with incidents a considerable distance from back-up in remote locations, and Taser has a critical place in protecting the public and officers as a less lethal device.
“Around one third of BTP officers are trained to carry Tasers and our specials have received the same comprehensive training as regular officers.”
Specials are volunteer officers who have the same powers as regular officers and are an integral part of BTP’s frontline personnel. The force employs 270 specials.
They work a minimum of 16 hours a month and are deployed shoulder-to-shoulder with regular officers, attending the same incidents across the rail networks of England, Scotland and Wales.