Low carbon alternatives for Severn Beach Line

Vivarail Class 230 Battery Electric Multiple Unit (BEMU) demonstration train

What can be done to decarbonise the Severn Beach line quickly? FoSBR supporter Shabs Hussain looks at some low carbon alternatives for Severn Beach Line.

Current situation

The Severn Beach Line is an urban rail service operated by Great Western Railway (GWR) which runs between Bristol Temple Meads and Severn Beach. Over 1.4 million passenger journeys were completed in 2019. Passenger numbers are set to grow further after the service was upgraded in December 2019 to run every 30 mins. Alternate trains now continue to Weston super Mare through Bedminster and Parson Street. We will also see the introduction of the new Portway Park and Ride station in summer 2022 which will be the first new railway station built in Bristol for 95 years.

Our urban railway lines are an essential service that that provides choices for those looking for alternatives to the car. They help ease congestion on the roads, reduce pollution and allow the region to work towards ambitious carbon and climate targets.

GWR operates a fleet of Class 166 turbo trains on the Severn Beach line. These were built over 30 years ago and use old diesel technology which needs urgent replacement. The trains cover the 22km distance from Temple Meads to Severn Beach through urban areas, passing near homes and generating noise and air pollution.

There are no active plans to electrify the Severn Beach line. The government has a proposal that states that electrification of trains will happen by 2050, but we need an interim solution that will service the growing needs of the community for up to the next 20-30 years.

This proposal details the solutions that we need your support to deliver. We must not continue to rely on 30 year old diesel trains to meet the growing needs of the community and meet our climate commitments.


The following criteria were used to shortlist two viable options

  • Is a ready to be implement solution – implementation delays kept to a minimum
  • Must use existing rail lines – no overhead power lines
  • Infrastructure changes kept to minimum – battery charging points at Bristol Temple Meads and Severn Beach station only
  • Use existing proven and mature electrification technology
  • Use manufacturers with a proven track record
  • Upcycle existing trains where possible – useful life extension and saving waste, energy and materials
  • Fixed known costs vs unknown large infrastructure changes
  • Significant reduction in pollution and noise for local residents that live near the train line
  • Helps meet ambitious carbon and climate targets
  • Increases passenger comfort
  • Reduced running costs

Option 1: Vivarail

  • Supply of Class 230 Battery Electric Multiple Units (BEMU) or Diesel Electric Multiple Units (DEMU)
  • These use bodyshells from London District Line trains which were discontinued from service
  • The trains are essentially brand new with everything replaced or upgraded depending on specification
  • This extends the useful life of existing good quality rolling stock, saving waste, energy and materials
  • Simple to charge at Temple Meads or Severn Beach station – 10 min fast charge
  • Operation in city, country or commuter routes
  • Maximum speed of 60mph (nearly 100km/h)
  • Zero emission (BEMU) or low emission (DEMU) with engine shut down at stations
  • Current operation:
    • Transport for Wales – Flagship fleet for the new Welsh franchise Wrexham-Bidston line
    • South Western Railway – Provide a zero emission service on the Isle of Wight
    • London Northwestern Railway – Bedford – Bletchley Line since 2019

Option 2: HybridFLEX

  • Convert the existing Diesel Turbo 166 class trains that service the Severn Beach line to diesel electric
  • No change to existing capacity
  • Uses a innovative MTU powerpack from Rolls Royce
  • The MTU Hybrid PowerPack® includes a combustion engine and an electric machine that can function both as a motor and as a generator which recovers energy during braking.
  • This energy is fed to a battery – the MTU EnergyPack®– where it is chemically stored, ready to power the vehicle whenever the train needs to travel quietly or accelerate quickly.
  • This extends the useful life of existing good quality rolling stock, saving waste, energy and materials
  • Can be charged at Temple Meads or Severn Beach station or on route using the diesel engine
  • The train can be programmed to use its battery in dense pollution areas to make best use of the energy
  • 75% cut in noise and emissions at stations, up to 25% fuel and CO2 emissions, up to 70% NOx emissions
  • 90% particulate reduction
  • Diesel engine meets future EU Stage V emissions regulations
  • Current operation:
    • Chiltern Railways – London Marylebone and Aylesbury

What next? When can this happen?

That depends on your support!

Please contact your local MP and local councillor to ask for their support with this proposal.

With their support funding can be sourced from Network Rail, West of England Combined Authority, Bristol City Council and Department for Transport to formalise this change.

With funding in place we could see the first new trains running on the Severn Beach line in the next few years.

Feel free to contact Friends of Suburban Bristol Railways for more information.



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