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Class 321 EMUs upgrades

Replace traction and auxiliary equipment packages for mid-life upgrades


Vehicle Class

Number of Cars






Scope of Work




Eversholt Rail committed to this investment ahead of the new East Anglia franchise being let with 10 off Class 321 EMUs being delivered into service with Abellio Greater Anglia by October 2016 and the remaining 20 off EMUs being offered for service after commencement of the new Anglia franchise.

Scope of work

To replace 30 traction and auxiliary equipment packages for the first batch of mid-life upgraded Class 321 EMUs.

Work carried out

In 2013, Eversholt Rail and GRT embarked on the pre- series project to demonstrate modern AC traction on a Class 321 unit. The key objectives were to reduce journey time for passengers, improve reliability and maintainability, and reduce the total cost of operation through a combination of reduced energy consumption and regenerative braking. The major change to the Class 321 EMUs traction packages included replacing the DC traction system with a modern lighter-weight 3-phase AC Insulated-Gate Bipolar Transistor (IGBT) traction system. The new AC traction system is contained in a single case and uses the same bogie frame and axle suspension tube mountings as the DC traction case. Reliability is improved by the reduction in the number of moving parts and lower maintenance requirements.

Kiepe Electric in Düsseldorf is responsible for the manufacture and delivery of the AC traction equipment including the Main Transformer, AC Traction Motors, Traction Converter, Auxiliary Power Supply Unit and the installation of a modern braking system with improved
wheel-slide prevention.

The traction system provides a regenerative braking facility that uses the traction motors as generators when the train is braking. The electrical energy generated is fed back into the overhead 25 kV traction power supplies and offsets the electrical demands of other trains on the same network. The upgraded units, given the programme name ‘Renatus’ by Eversholt Rail, will follow the work being undertaken by Wabtec in their Doncaster facility to vastly improve the Class 321 EMU passenger environment.

Key benefits

Enhancing rolling stock to meet passenger expectations and reduce costs to the UK rail industry with the Class 321 product upgrade matching the quality and performance of a new train.

“We are delighted to have secured this contract for new and modern GRT traction equipment for the Eversholt Rail Class 321 Fleet. Our clear focus is on ensuring that our newly fitted traction equipment and integrated braking enhancements deliver a highly reliable and greatly improved Class 321 performance level for Eversholt Rail, the train operators and the passengers that use these trains in future years.”


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