2. Assessing energy requirements

2.1 Rolling load characteristics

The electrical charge generated by trains is not a constant charge, as the talk of "standard operation" would have us believe. In fact, the current curve (figure 2 ) picked up by a moving train is characterized by a succession of inrushes and outrushes of current on the contact line (starting and braking), spaced out by periods of low load (load on vehicle auxiliaries) corresponding to stops and runs over the track. Electrical energy consumption results mainly from :

• energy dissipated in the brakes (significant in the absence of recuperation);

• resistance to forward motion (air resistance,...