L-R: David Brown (Managing Director, Arriva UK Trains), Richard Allan (Managing Director, Chiltern Railways), Mike Cooper (CEO, Arriva UK Trains), Mary Grant (CEO, Porterbrook) & Warren East (CEO, Rolls-Royce)

Chiltern Railways celebrates 25th anniversary with launch of greener and quieter HybridFLEX train

  • Chiltern Railways and partners invest in green HybridFLEX train, delivering emission-free battery operation, reducing CO2 (¯25%), nitrous oxide (¯70%) and particulates (¯90%)
  • Rail Minister Chris Heaton-Harris MP is supporting the launch event at Marylebone station, before key stakeholders travel on board HybridFLEX, Britain’s first hybrid battery-diesel train
  • Chiltern – the operator of train services between Birmingham, Oxford and London – today celebrates 25 years of continuous service for customers

Chiltern Railways will mark 25 years of achievement as a train operator with a celebration event at London Marylebone Station and the launch of HybridFLEX – Britain’s first battery-diesel train. Chiltern is currently an all-diesel operator with an average fleet age of 25 years. A key priority for the operator is to help deliver decarbonisaiton for the UK by investing in innovation.

Long-serving Chiltern colleagues will be joined at Marylebone Station by regional stakeholders and rail industry executives, prior to the train travelling to Bicester Village on its maiden journey.

The HybridFLEX train will arrive into London Marylebone station at 1000 on 21 July. Following a programme of speeches, the guests will take a closer look at the HybridFLEX train before it departs from the station at 1030. The train will then arrive at Bicester Village at 1120 where there will be further activities to commemorate Chiltern’s silver anniversary.

HybridFLEX train

HybridFLEX is the product of collaboration between rolling stock owner and asset manager Porterbrook and engineering giant Rolls-Royce. As well as offering zero emissions and near silent operation at stations, the Rolls-Royce Hybrid PowerPack will also reduce fuel consumption and so CO2 emissions by up to 25%, Nitrous Oxide (NOx) emissions by over 70% and particulate emissions by over 90%, compared to the engines it replaces.

Chiltern is delighted to be trialling this new technology to demonstrate that it can contribute to better air quality, decarbonisation and the aim of removing traditional diesel trains from its network. The HybridFLEX aims to enter full passenger service from September this year.

Rail Minister Chris Heaton Harris said: “HybridFLEX trains will make rail travel even greener and the air in our stations cleaner.

“Chiltern Railways have connected people for a quarter of a century and now are helping to prepare for the future as we build back greener.  This is a great example of how innovation and enterprise can help us reach our ambitious target of net zero emissions by 2050.”

Richard Allan, Managing Director at Chiltern Railways said: “Chiltern has a fantastic track record of innovating and investing in new routes, stations, depots and trains to attract and retain customers. We are proud and privileged to mark our 25th anniversary by introducing colleagues and stakeholders to the HybridFLEX train. We need to modernise Chiltern again and this exciting use of new technology in an older train is a potentially very significant opportunity to help us decarbonise and improve our customer experience."

Mary Grant, CEO of Porterbrook said: “We are delighted to be able to support Chiltern Railways’ ambitious plans for the future. Our HybridFLEX, built in partnership with Rolls-Royce, will offer improved air quality and reduced noise at stations and other sensitive locations on the Chiltern network.

“HybridFLEX is part of Porterbrook’s growing portfolio of alternative traction systems designed to help Britain’s railway accelerate the race to Net Zero.”

Warren East, Chief Executive Officer at Rolls-Royce said: “This collaboration demonstrates the pivotal role technology is already playing in the transition towards a net zero future. With 1.7bn passenger rail journeys taking place every year in the UK, the 25% reduction in CO2 emissions offered by HybridFLEX represents a meaningful step forward in the country’s journey towards its 2050 net zero target. We’re delighted to be part of this ground-breaking team with our hybrid solution alongside Chiltern Railways and Porterbrook.”

Delivering innovation and growth for Chiltern customers

  • Chiltern Railways is the only surviving, continuous train operator brand since privatisation. Customer feedback around the Chiltern Railways brand is very strong.
  • Over two decades, Chiltern has seen customer numbers grow from 8 million (1999) to 29 million (2019).
  • Chiltern has invested over £600 million into the network over the past 25 years, including £250 million to speed up journeys between London and Birmingham.
  • Chiltern made a £320 million investment in partnership with Network Rail to open a new rail link between Oxford and London, the first new route connecting a city with the capital for 100 years - delivering faster and more frequent journeys.
  • Chiltern has built new stations at Oxford Parkway, Warwick Parkway, Aylesbury Vale Parkway and Bicester Village; restored a once-derelict Birmingham Moor Street station; and reconstructed Haddenham & Thame Parkway station.
  • Chiltern oversaw the delivery of new platforms at Moor Street, Marylebone, Princes Risborough, Islip and Oxford.
  • The number of weekday services run by Chiltern increased from 240 to over 430 before the Covid-19 pandemic
  • New Chiltern depots have been built at Wembley and Banbury to ensure reliable rail services.
  • Chiltern invested in a fleet of new Class 168 trains in 1996, the first order for new trains placed by any privatised train company.
  • Chiltern was the first operator to offer onboard Wi-Fi and first to have a presence on Twitter.

Contact Information

Notes to editors

Media Contacts

Chiltern Railways

Laura Jones, PR and Press Office Manager

Laura.jones@chilternrailways.co.uk or +44 (0)7971306188


Rupert Brennan Brown, Director of Stakeholder Engagement 

Rupert@porterbrook.co.uk or +44 (0)7973 950 923

PR enquiries for Porterbrook can also be directed to:

 Portland Communications                

Richard Brooks, Consultant

Richard.Brooks@Portland-Communications.com or +44 (0)7740 858477

About Chiltern

  • Chiltern Railways is part of the Arriva group, one of the leading providers of passenger transport in Europe, employing 53,000 people and delivering 2 billion passenger journeys a year across 14 European countries. Arriva are part of Deutsche Bahn (DB), one of the world’s leading passenger and logistics companies, responsible for DB's passenger transport services outside Germany.
  • Chiltern operates commuter/regional rail passenger services from its Central London terminus at London Marylebone along the M40 corridor to destinations in Buckinghamshire, Oxfordshire and Warwickshire, as well as long-distance services to the West Midlands along two routes. Services on the Chiltern Main Line run from London Marylebone to Birmingham Snow Hill, Stratford-upon-Avon and Oxford, with some peak-hour services to Kidderminster.
  • Chiltern also runs trains on the London to Aylesbury Line to Aylesbury (with some trains terminating at Aylesbury Vale Parkway instead), on the Princes Risborough to Aylesbury and Oxford to Bicester branch lines.

About Porterbrook

  • Porterbrook has been at the heart of the UK rail network for over 25 years and owns over a quarter of the national passenger rail fleet. We provide high-quality, digitally enabled rolling stock which helps deliver a safe, reliable and sustainable railway
  • We currently have around 4,000 vehicles on lease or on order. Since privatisation, we have invested £3bn in new passenger and freight vehicles, and we are looking to invest a further £1bn in Britain’s railway over the coming years
  • Our role as a leading asset owner and manager goes well beyond financing. Our rolling stock is designed to serve 30-35 years in front-line service. By ensuring that these vehicles live out their full asset life, with periodic upgrades and enhancements, we maximise value to passengers and taxpayers, whilst minimising carbon emissions and environmental impact
  • Innovation is at the heart of Porterbrook’s approach to whole life asset management. In collaboration with industry and academic partners, we are developing a portfolio of digitally enabled and re-tractioned rolling stock. Our business is at the forefront of developing of hydrogen, hybrid and battery powered trains. We are also working with SMEs and Innovate UK to significantly reduce emissions from our existing diesel fleets.

About Rolls-Royce Holdings plc

  • Rolls-Royce pioneers the power that matters to connect, power and protect society. We have pledged to achieve net zero greenhouse gas emissions in our operations by 2030. We joined the UN Race to Zero campaign in 2020 and have committed to ensuring our new products will be compatible with net zero by 2030, and all products will be compatible with net zero by 2050.
  • Rolls-Royce has customers in more than 150 countries, comprising more than 400 airlines and leasing customers, 160 armed forces and navies and more than 5,000 power and nuclear customers.
  • Annual underlying revenue was £11.76 billion in 2020 and we invested £1.25 billion on research and development. We also support a global network of 28 University Technology Centres, which position Rolls-Royce engineers at the forefront of scientific research.
  • Rolls-Royce Holdings plc is a publicly traded company (LSE:RR., ADR: RYCEY, LEI: 213800EC7997ZBLZJH69).