The closest that's actively used is Wabtec's FLXdrive, which is a battery-powered locomotive run between two conventional diesel-electrics. Not a bad idea, since braking with the electric motors otherwise dumps the energy as waste heat. There's also the Railpower Green Goat, which is diesel-electric with a storage battery.

https://trn.trains.com/news/news-wire/2021/01/04-wabtecs-flx...

https://en.wikipedia.org/wiki/Railpower_GG20B