Restrained Base Feed Rigid High Tower Model
In this variant, the lowest body fed into the rising tower has its radial velocity restricted to 2 km/sec. This could be achieved if the tether from ground to the lowest body were kept in tension, to stop the lowest body from accelerating too fast.
This tower maintains an average radial velocity of 2 km/sec along its length. It takes a single body some 35 hours to rise from the planet surface to the 250,000 km radius tip of the rigid tower. Acceleration from zero radial velocity to 2 km/sec reaches 3g. But in this model, the journey up the tower is no smooth ride: body radial velocity oscillates around 2 km/sec, but can reach 4 km/sec, and fall as low as 0.5 km/sec, with accelerations of 3-4g. Rather like a ripples running down a long freight train. This happens because releases from the top, and constraints at the bottom generate forces which propagate up and down the tower.