UK’s Chiltern Railways secures 13 modern trains to be fueled by renewable diesel

Photo: Chiltern Railways

In a boost for regional growth, Chiltern Railways announced in August that it has secured modern trains to transform customer journeys in Buckinghamshire, Oxfordshire, Warwickshire and the West Midlands in the U.K. 

Chiltern Railways, which is part of Arriva Group, will replace its oldest carriages (Mark 3s) with 13 modern trains (Mark 5As), which will carry customers along one of its three main routes, between London and the West Midlands, from spring 2026. 

Chiltern has decided to fuel these newer trains with hydrotreated vegetable oil (HVO), also known as renewable diesel, a biofuel that reduces carbon emissions and cuts pollutants compared to conventional diesel.

Chiltern has also contracted the owner of the trains to fit the latest stop-start engine technology software, helping to further reduce emissions for lineside neighbors. 

First-class carriages will also be introduced on the route in 2026, offering more spacious seats and improved connectivity for business and leisure travelers.

New features for customers will include plug sockets and USB ports at every seat, enhanced Wi-Fi and digital customer-information screens.

Customers will also benefit from onboard air conditioning, improved luggage and bike storage, and dedicated accessible areas including fully accessible toilets. 

“We are thrilled for our customers that we will be able to replace our oldest trains, which are nearly 50 years old, and replace them with their modern equivalent that are just six years old and provide significant improvement to their onboard experience,” said Richard Allan, the managing director of Chiltern Railways. “Chiltern will be renting more trains than it has today, which means we can operate additional services from the end of 2026 to help meet rising demand. The trains will be formed of modern carriages hauled by locomotives fueled by recycled vegetable oil and fitted with the latest stop-start engine technology.”

Allan continued, saying, “Our 2030 vision includes a three-phase plan to modernize and decarbonize our trains. Phase 1 is underway with interior improvements to our existing diesel trains. Phase 2 is to replace our oldest trains—today’s announcement. We remain ambitious and determined to achieve Phase 3 of our vision, which is to replace our 35-year-old diesel trains with battery-electric trains.” 

U.K. Rail Minister Lord Hendy added, “This government is putting passengers back at the heart of the 21st-century railway by investing to make journeys easier, greener and more comfortable. We are continuing to support Chiltern as they develop a plan to introduce additional services into their timetable, giving people more opportunities to work, live and socialize. Great British Railways will unite our railway with one mission—delivering excellent services for passengers wherever they travel, and improving connectivity, driving growth, jobs and homes as part of the government’s plan for change.” 

Adam Cunliffe, the CEO of Beacon Rail, said, “Beacon is delighted to support Chiltern with the lease of the Mark 5A fleet, providing additional capacity with new trains that will enhance the passenger experience. Working closely with the Department for Transport and Chiltern, the introduction of the Mark 5As reflects the strong collaboration that Beacon provides to its customers. Beacon is engaging with Chiltern to commence services by spring 2026.” 

Following a positive decision from the Department for Transport, these newer trains will enter service on a phased basis from early next year as a crucial step in delivering Chiltern’s 2030 vision of easier, greener and better journeys. The operator is also working with partners to confirm details of additional timetabled services, which would start in December 2026.