The 776m-long shuttles allow passengers to remain in their vehicles during the 35-minute Channel crossing.
In the 25 years since the Channel Tunnel opened, the shuttles have travelled an average of 300 round trips per month each and carried more than 236 million passengers between France and Britain.
Deliveries of the newly refurbished shuttles will start in mid-2022 and continue until mid-2026.
The shuttles were originally built by the Euroshuttle Wagon Group consortium of GMT-Bombardier, BN and ANF Industrie, with bogies coming from GEC-Alsthom.
Bombardier will be responsible for the renovation of 26 wagons on each of the nine shuttles, including 12 single-deck coaches for buses, minibuses, caravans and vehicles over 1.85m-high, 12 double-deck coaches for cars and motorcycles, and two double-deck loader wagons, in addition to two spare loader wagons.
As project technical advisor, Bombardier will lead the integration and renovation operations on the cars, except for the single-deck loaders, and will lead the engineering design and procurement for onboard equipment.
Eurotunnel will undertake design and procurement of key equipment such as brakes, doors, fire doors, fire detection, HVAC and the double-deck loaders, and will also manage the certification process of the renovated shuttles. Bombardier will provide technical support to prepare the required documentation.