Home Rail News Hydroflex - the next iteration of the Flex concept

Hydroflex – the next iteration of the Flex concept

When researching an article for the Class 769 Flex, there were lots of ideas discussed about how the concept could be extended for other uses. What was not discussed was the possibility of a hydrogen-powered version. Yet, at InnoTrans on 19 September, in the presence of the Secretary of State for Transport Chris Grayling, Porterbrook announced that it was making a Class 319 unit available to Birmingham Centre for Railway Research and Education (BCRRE) for conversion into a hydrogen-powered train to be known as HyrdoFlex.

The announcement added that development work has recently commenced and HydroFlex will undertake testing and demonstration runs in summer 2019.

The HydroFlex will retain the ability to operate on existing electric routes (on either third rail or 25kV overhead power) and the addition of a hydrogen fuel cell will allow it to operate in self-powered mode, without the need for diesel engines.

As was reported in Rail Engineer earlier this year, Rail Minister Jo Johnson has challenged the rail industry to develop decarbonisation plans, with the objective of removing diesel-only trains from the network by 2040. HydroFlex is Porterbrook’s and BCRRE’s response to this challenge, bringing together industry and academia in partnership to deliver the UK’s first-in-class, clean energy, main line passenger train.

After the signing ceremony, the Secretary of State joined representatives from Porterbrook and BCRRE to discuss both the potential for hydrogen technology to decarbonise the railway and the world-leading rail R&D and innovation expertise to be found across the UK rail supply industry and through the UK Rail Research and Innovation Network (UKRRIN).

BCRRE reported that it has already undertaken a significant amount of research into the potential application of hydrogen fuel-cell technology to railway operations and has worked with a number of global rail businesses to identify potential opportunities to use hydrogen as a clean alternative to diesel.

Strictly a demonstrator

Rail Engineer readers who have been following this topic will understand that the Class 319 is not necessarily the best base for a hydrogen-powered train – the lack of regenerative braking might lead to a bigger fuel cell, for example. Clearly, if the objective was a fully developed train ready for production, then this might be a problem, but this is not the key objective at this stage of the project.

In response to Rail Engineer’s questions, BCRRE said that the demonstrator version focuses on delivering an electric/hydrogen bi-mode to UK gauge, which the UK market is currently looking for given the wider context of the 2040 decarbonisation ambition and the need to make more effective use of existing electrification with additional emission-free running beyond the wires.

BCRRE added that a part of the project includes developing the product approval and safety cases for hydrogen running on the UK railway.

The team working on this demonstrator project has a lot of work to do to make hydrogen rail a reality. The demonstrator will take passengers in 2019, but BCRRE will need to prove the technology to the regulator and the infrastructure manager before the demonstrator can go into full passenger service.

BCRRE promised more technical details later, so watch this space!

Read more: Bi-Mode Good, Try-Mode Better


Malcolm Dobell BTech CEng FIMechEhttp://therailengineer.com

Rolling stock, depots, systems integration, fleet operations.

Malcolm Dobell worked for the whole of his 45-year career with London Underground. He entered the Apprentice Training Centre in Acton Works in 1969 as an engineering trainee, taking a thin sandwich course at Brunel University, graduating with an honours degree in 1973.

He then worked as part of the team supervising the designs of all the various items of auxiliary equipment for new trains, which gave him experience in a broad range of disciplines. Later, he became project manager for the Jubilee Line’s first fleet of new trains (displaced when the extension came along), and then helped set up the train refurbishment programme of the 90s, before being appointed Professional Head of Rolling stock in 1997.

Malcolm retired as Head of Train Systems Engineering in 2014 following a career during which he had a role in the design of all the passenger trains currently in service - even the oldest - and, particularly, bringing the upgraded Victoria line (rolling stock and signalling) into service.

He is a non-executive director of CPC Systems, a systems engineering company that helps train operators improve their performance. A former IMechE Railway Division Chairman and a current board member, he also helps to organise and judge the annual Railway Challenge, is a member of the Railway Division Board and is the chair of governors at a large secondary academy in Milton Keynes.


  1. What about the Class 317s. They could be converted as Bi-Mode Class 317 “Flex” and to operate them on several routes in England. As the Class 317 on Greater Anglia & London Overground are to be replaced by the Class 710, Class 720 and Class 745.


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