GANTRY SCAFFOLD
A massive scaffolding structure mounted on a bridge or platform supported by a pair of towers or trestles that normally run back and forth on parallel tracks, used to assemble and service a large rocket on its launching pad. Often shortened to "gantry". Also called "service tower". This structure is a latticed arrangement of girders, tubing, platforms, cranes, elevators, instruments, wiring, floodlights, cables, and ladders - all used to attend the rocket.