xcX3v84RxoQ-4GxG32940ukFUIEgYdPy from <Here is a link to a video of people riding a recumbent tandem. < The video does a good job of explaining that the front crank has a freewheel mechanism that lets the riders pedal at different speeds. The front rider can also stop pedaling.If this is what is meant as "independent drivetrains" then the functionality is in the crank rather than the frame itself.The key to having a regular tandem like the recumbent tandem in the video is to find someone who makes a crank with a freewheeling chain ring. Like the old school Schwinn Suburban's from the late 70s with Shimano Positron FFS (Front Freewheel System