Powering urban rail vehicles

To date, no other energy source than electricity has been sustainably used to operate urban rail vehicles. From the outset, the Paris Metropolitan Railway has used electricity, which was, and still is, the only energy that offers all the qualities needed to operate an efficient underground urban transport network.

Wherever it is consumed, it causes little pollution. In fact, when it is used, it entails no harmful emissions for humans or the environment, and the machines that transform it into mechanical energy emit little noise or vibration. In the case of an exclusive right-of-way transport system, it can be easily distributed to vehicles on the road, which then don't have to store energy in heavy and potentially dangerous underground tanks. Energy losses in the circuits and electrical machines generated by the operation of vehicles and auxiliaries are low, considerably limiting heat dissipation in tunnels and underground stations.

Over the years, air pollution and noise have become increasingly important concerns for cities. Rediscovering the virtues of electricity for surface transport, transport authorities have pushed for the renewal of tramway lines. Added to these considerations is the realization that without electricity and its distribution systems, public rail transport would not be able to offer today's high level of service, in terms of capacity, performance, availability and quality. It is therefore clear that the electrical power supply and distribution system is an essential component of any urban rail system.

This power supply system for urban railways calls on its own technical solutions, which are best suited to the specific characteristics of urban transport, its operation (numerous stops, high speeds, short parking periods) and its environment (tunnel, public highway). This issue is devoted to the system's main function: powering the vehicles.

We propose to show how this system has adapted over time:

• increased sales performance and energy consumption;

• increased service continuity and safety requirements, particularly in automated operations;

• the changing constraints of the urban environment and energy supply.

We also give an overview of the design rules generally applied in France, in particular for :

• functional architecture ;

• electrical diagrams ;

• equipment sizing ;

• energy management.

We'll be looking at applications for metro, RER and tramway systems.