Tucked into your control system pathways, you will also find a little gadget called a POGO. These give you the ability to maintain control although your flight control system is partially jammed. This item fits the category of "mechanical override systems" referred to in the previous posting. Rather than describe them myself, I figured that I would let a professional take that task. See
Pogo Load Limiter
Now take a look at this simplified diagram of the elevator control on the 737NG (courtesy of Peter Lemme's Blog) Do you see the POGO?
Well, I said this is simplified. There has to be another set of Pogo-like mechanisms connecting the left and right control cables to the elevator input torque tube or else there would be no point to having the breakout mechanism discussed in my previous post.The two columns would be locked together through the elevator input torque tube. Consider the implications of what happens when the crew hauls back hard against the elevator feel and centering unit resistance!!
737-300 Elevator Control