And diesel hydraulic trains (and some buses) usually use these: https://en.wikipedia.org/wiki/Retarder_(mechanical_engineering)#Hydraulic_retarder https://en.wi

And diesel hydraulic trains (and some buses) usually use these: https://en.wikipedia.org/wiki/Retarder_(mechanical_engineering)#Hydraulic_retarder https://en.wikipedia.org/wiki/Retarder_(mechanical_engineeri...