And yet no-one is rushing to retrofit batteries to old EMUs to take advantage of this rapidly improving technology.
After the turntide batteries on the 802 which may or may not still be fitted (I'm no longer in position to give a... <insert your own words here>), and numerous ideas for 'decarbonisation' including the same battery packs, different battery packs, conversion of EMUs, DMUs, and addition of hybrid drives to other vehicle types to give advantage on mixed traffic railways.
None of these, and I mean, none have been commercialised. And very few ever turned a wheel in anger, or even got close to it.