>>1988780>So regenerative braking isn't common, if ever it even happens, in AC.I don't think that's the case. I can't speak to the technical details - my layman's guess is that the process for getting electrical energy from an overhead cable -> electrical systems -> wheels turn, is completely reversible - but it's absolutely possible for AC trains to re-use braking energy to feed energy back into the grid, rather than simply dissipating it as heat. Here's an example, from page 5 in the booklet:
>https://www.lner.co.uk/globalassets/lner1461-cop-26-environmental-sustainability-report-a5-booklet-v6---digital-copy-min.pdf