Doing this in a non-spherical-cow environment will be challenging, because the gravitational load varies (passengers stepping on/off) but it's probably importan

Doing this in a non-spherical-cow environment will be challenging, because the gravitational load varies (passengers stepping on/off) but it's probably important to keep the velocity fairly constant to avoid upsetting the balance of those standing on it, let alone those walking down it. So it likely needs the generator load to be very responsive to the behavior of a long loop of rather heavy objects with quite a lot of friction, motor driven via reducing gears. Maybe instead of thinking of generation, it's more a question of regulating the applied motor power to keep constant velocity?