Leaving the train at 1/3rd the speed it decelerated from?
What’s really happening:
Barcelona want to use regen braking to reduce power usage of their metro - this is good.
Adding batteries to store all that energy for 30seconds at each stop is impractical in some way. It makes the train too heavy / They can’t charge quick enough / The charging loss is too high. So, they go for a smaller battery.
The electrical grid gets the rest of the energy dumped into it, only to supply it back to the train when it accelerates again. They use the grid like a battery.
Some public relations person heard this and issued a press release - “Barcelona using metro as power station”.
Every engineer working on the project simultaneously groans in despair. The resulting low frequency wave shakes the foundations of Sagrada Família, setting the construction back another generation.
Why can’t they use the excess energy to make the train go again?
They do… 1/3rd of it is used that way.
Leaving the train at 1/3rd the speed it decelerated from?
What’s really happening:
Barcelona want to use regen braking to reduce power usage of their metro - this is good.
Adding batteries to store all that energy for 30seconds at each stop is impractical in some way. It makes the train too heavy / They can’t charge quick enough / The charging loss is too high. So, they go for a smaller battery.
The electrical grid gets the rest of the energy dumped into it, only to supply it back to the train when it accelerates again. They use the grid like a battery.
Some public relations person heard this and issued a press release - “Barcelona using metro as power station”.
Every engineer working on the project simultaneously groans in despair. The resulting low frequency wave shakes the foundations of Sagrada Família, setting the construction back another generation.