Series hybrid drivetrains are worse efficiency at highway cruise speeds. The mechanical double conversion is much worse than a straight mechanical transmission.

Series hybrid drivetrains are worse efficiency at highway cruise speeds. The mechanical double conversion is much worse than a straight mechanical transmission. They only make sense in city stop go which is why nearly all hybrid cars are parallel and connect ICE to wheels at highway speeds. Trains sacrifice drivetrain efficiency in order to get precise traction control to prevent wheel spin and to greatly simplify power routing to bogies. They make up for the efficiency loss with low rolling resistance steel wheels on steel track and really good aero due to long trains cars all drafting.