Because one part is bolted to the cabinet and the other to the drawer, they need to be separated. The manual says it's a friction fit, that's all. No further instructions on how to disassemble them. I had to clamp them in a vice and finally overcome the so-called frictional connection with a crowbar. Other drawer fittings just push a small latch and they instantly separate. Not this one. Very bad design. After taking them apart, I realized that if I ever had to take the box out, I'd probably have the same problem. This is a real killer. I returned them. Are you still looking for a central mounting rail that can be easily disassembled for assembly and after assembly allows for easy disassembly of the drawer if necessary. Follow up: I assumed I could return this item. Turns out I couldn't, it's no return. Buyer warning!