Me too (that about "one line" was a braintzypo :-))
Electric cars do have regenerative breaking which I assume Citadis doesn't have (no battery / no injection).
No, electric trains don't feed back into a battery, but into the catenary. With the spread of AC motors and modern power electronics, using the motors as generators is no problem. However, the system is most efficient and convenient if the catenary is on a rail-only AC grid, and least if it is fed DC (limited uptake, adverse effects of change in voltage) -- and trams are fed DC.
However, with some search, I found the new trams do use regenerative braking, even if to a limited extent. I now found that one light rail project on Tenerife, which calculated with Citadis trains (and wind turbines as power source), expects 20% energy savings from regenerative braking.
I don't know why train don't appear that efficient in energy use
Because the bus (and plane) advocates' numbers are spun?
I should dig up numbers about this, I long promised the same on high-speed trains to Luis de Sousa too, but certainly not on the workdays this week, I'm too busy.
kcurie link says for Citadis 302 in Spain:
Note: even trains/trams of the same model can differ strongly (not only in front styling and seating, but carbody width). Modular construction makes it possible. *Lunatic*, n. One whose delusions are out of fashion.
For comparison I mostly refer to electric car numbers which do exist for a wide variety of cars (including cars in use by customers) and are all more or less the same so I think we can trust them.
A few diaries ago I said I would ask http://www.effet-de-serre.gouv.fr/ and they just answered me today citing page 33 of this PDF:
http://www.effet-de-serre.gouv.fr/images/documents/memento.pdf
Which gives the following relative energy use for passenger-km:
Walk/bike 0 Paris Tramways 0.10 Paris subway 0.13 Paris RER 0.14 Paris "banlieue" trains 0.21 Paris area buses 0.44 France buses 0.56 Motorcycle 0.62 Individual car 1.0
(I don't know if the car data is for one passenger only ... these "green" paper could be more informative).
So there is a Citadis model that does power injection
The way I understand it, it an inherent feature (it should be with IGBT inverters), and use depends on whether the tram line power supply was made suited. With some more search, I found other examples of active use (Rotterdam, Sydney, Basel, etc.), so it may not be uncommon. Recovery rates are usually low, but in Basel, a phenomenal 41.6% was achieved with Siemens Combinos in a test. The latter link also gives you kWh/km figures (page 8). *Lunatic*, n. One whose delusions are out of fashion.
If I do the math on the Basel data:
