The first train in Great Northern’s modern new fleet is being tested without passengers on the King’s Lynn route.
Complete with air conditoning, the new trains are to enter service later this year, replacing many of the existing trains.
Features include two-by-two seating with tables, power points at every seat and fully-accessible toilets.
Gerry McFadden, engineering director at Govia Thameslink Railway, said: “These modern trains are great for people with disabilities and all passengers will love the two-by-two seating and the power points at every seat.
“The air-conditioning, a first for the route, will keep people cool and comfortable in the summer months.”
The project is part of an overall plan to replace almost all the trains on the Great Northern route by 2020.
The remaining trains are to under go a £30m refurbishment programme.
Mr McFadden added: “In just a few short years, we’ll be moving from one of the oldest fleets in the country to one of the newest.”