GREENTECH: CAF's solution to the catenary-free tram

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Video transcript:


Greentech is an ambitious initiative developed by CAF Power & Automation aimed at offering a range of the most efficient and eco-friendly products. The main advantages of this system are optimising energy consumption and reducing the visual impact of the tram in the city centre, thanks to the elimination of the catenary.

Within this line of CAF Power & Automation products, there are 2 different technologies, both applicable to any articulated vehicle platform: Greentech Evodrive and Freedrive.

Greentech evo Drive

Greentech Evodrive is an on-board system that recovers the kinetic energy released in braking, allowing trams to use it and improve the energy efficiency of the vehicle.

This system, based on supercapacitors is specifically designed for trams with a conventional traction system, the energy recovery of which is difficult to return to the catenary.

This system consists of:

  • A storage system: supercapacitor modules and/or the latest generation batteries capable of storing energy.
  • A DC/DC converter: manages the charging and discharging of the storage system.
  • Control electronics: incorporates advanced strategies for the optimum control of energy flow.

In this way, the energy supply is optimised and energy savings is achieved.

Greentech free Drive

Greentech Freedrive is an on-board energy storage system that allows catenaryfree movement.This system, based on lithium-ion supercapacitors and batteries, includes Evodrive technological advantages, being easily integrated into new or existing railway systems, regardless of their make and structure.

CAF has the ability to adapt to different operational scenarios with catenary-free tram operations, through the hybrid combination of lithium-ion supercapacitors and batteries. In this way, parameters such as performance, autonomy, cost and traffic type are optimised.

Freedrive operation

1. The vehicle starts to run with the Freedrive system fully charged.

2. While it travels from one stop to another the Freedrive powers the traction system.

3. During the braking process the kinetic energy generated is stored in the Freedrive, starting its recharging process.

4. When the vehicle arrives at the stop the Freedrive system recharging process is completed.


  • It allows vehicles to operate in catenary-free sections.
  • Variable autonomy: from a typical distance of hundreds of metres to many kilometres thanks to lithium batteries
  • Reduction in the level of visual intrusion.
  • Reduction in investment in infrastructure.
  • Elimination of catenaries in sections, reducing visual intrusion in urban environments.
  • Non-proprietary system, applicable to any new or existing manufacturer and infrastructure.
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