A £4m project to install CCTV security cameras in all carriages on trains without conductors on a main route into London is part of a crime crack down.
Every carriage is fitted with a CCTV security camera
One Railways' services between Norwich and the capital, travelling through Suffolk and Essex, have received the extra security measures.
The aim is to give passengers more confidence when travelling by train.
More than 600 carriages now have CCTV security - about 60% of One's fleet - as part of its train crime campaign.
The company now plans to install CCTV at its stations.
Jonathan Denby of One Railways said: "Now we've got CCTV in every single carriage we can give passengers the extra reassurances they need to travel by train at any time of day.
"The CCTV cameras should make passengers happier and more comfortable about taking the train.
"The development is an important part of our campaign to fight crime."