The choice of energy source and power supply for a transport system is a major choice for any new construction project, or when converting or renewing a fleet of combustion engine rolling stock to cleaner energy alternatives. A stable, reliable and efficient electrical network is essential to operations, and its sizing is based on many external factors that require complex preparatory calculations.

The design of the electrical architecture is essential to ensure the high reliability of any transport system, even in degraded mode. On the other hand, oversizing the electrical system generates significant capital expenditure.


The electrification of railway lines offers considerable benefits in terms of reducing carbon emissions, improving performance and reducing operating costs. Given that the initial investment is likely to be significant, it is important to ensure that the functional requirements are carefully established.

For lines where electrification is not an option, alternatives to diesel traction may be considered, such as hydrogen power (fuel cells) or battery-powered trains. Here again, the initial investment must be based on appropriate requirements.

For metro projects, energy savings can be achieved on an existing network through the use of energy-efficient equipment and adjustments to optimise operations.


We design the electrical architecture to ensure that the transmission system is cost-effective and as reliable as possible, even in degraded mode. We pay particular attention to electromagnetic compatibility, which can have a considerable impact on system stability and performance, by limiting the risk of stray currents.

We are constantly looking for solutions that make the best possible use of technology to help our clients. For example, we were the first to deploy ground power supply on the Bordeaux tramway, and then on the longest line in the world with the Dubai tramway, offering discrete power supply without overhead contact lines, thanks to SYSTRA’s specifications.


We support our clients throughout the lifecycle of a project, from the feasibility and specification stages, through supervision of the works to the testing and commissioning phases.

We learn from projects around the world and offer our clients the most appropriate (and sometimes the most innovative) solutions. Whether by catenary or third rail, with battery-powered trams or hydrogen trains, we tailor solutions to meet today’s and tomorrow’s demands, while remaining cost-effective.

In addition to the services we provide to infrastructure managers and operators, we also work with the manufacturers responsible for producing power and traction systems.


The projects we undertake are always the result of close collaboration between our teams, our clients and our partners. And it’s they who say it best.

“SNCF Réseau entrusted SYSTRA with the electrification work on the Gretz-Troyes line, one of the objectives of which was to reduce greenhouse gas emissions in response to environmental challenges. This was a real collective success, as the work was carried out without any complete interruption to traffic, so as to minimise the impact of the works on users.”

Séverine Lepère, Deputy Director General Île-de-France, SNCF Réseau

Did you know

SYSTRA was one of the engineering consultants involved in the Téléo cable car project in Toulouse, France, which is 100% solar-powered.

See our expert insight:
Energy transition: public transport leads the way

At the forefront of encouraging sustainable mobility, SYSTRA engineers share their experience through a series of articles on the energy transition, drawing on years of practical experience in the planning, design and implementation of public transport projects around the world.