Rolls-Royce and UK-based passenger rolling stock owner Porterbrook have signed a letter of intent (LOI ) for the delivery of MTU Hybrid PowerPacks for installation on two test trains.

The MTU Hybrid PowerPacks are capable of converting Class 168 and Class 170 ‘Turbostar’ diesel multiple units (DMUs) from diesel-only to hybrid-electric operation.

Under the LoI, Rolls-Royce will initially supply two MTU Hybrid PowerPacks based on type 6H 1800 engines to Porterbrook.

The hybrid systems are scheduled to be installed on a Turbostar DMU by 2020 and will then be tested for a period of six months during regular operations.

Based on systems performance, Porterbrook plans to offer customers the opportunity to convert their existing Turbostar fleets into HybridFLEX trains by installing the MTU Hybrid PowerPacks.

Under the agreement, both parties will have an option to retrofit a second DMU with two MTU Hybrid PowerPacks.

“The environmentally friendly drive system integrates the use of diesel and battery-powered rail traction.”

Rolls-Royce CEO Warren East said: “With the innovative MTU Hybrid PowerPacks, Rolls-Royce and our partner Porterbrook will be setting new standards on the UK network; helping to reduce emissions, increase fuel efficiency and improve the lives of people who live near train stations.”

In addition, installation of MTU Hybrid PowerPacks on its trains is expected to help Porterbrook support the challenge of removing diesel-only trains from the country by 2040.

The environmentally friendly drive system integrates the use of diesel and battery-powered rail traction.

Porterbrook’s MTU Hybrid PowerPack features an MTU diesel engine to comply with future EU Stage V emissions regulations, as well as an electric machine that can be used either as an electric motor or generator.

It also comprises an MTU EnergyPack battery system that is designed to store the energy recovered during braking.

The system is set to allow low-noise, emissions-free battery-only electric operation in urban areas and around stations.